Recent zbMATH articles in MSC 83https://www.zbmath.org/atom/cc/832021-04-16T16:22:00+00:00WerkzeugM-theory and orientifolds.https://www.zbmath.org/1456.140462021-04-16T16:22:00+00:00"Braun, Andreas P."https://www.zbmath.org/authors/?q=ai:braun.andreas-pSummary: We construct the M-Theory lifts of type IIA orientifolds based on \(K3\)-fibred Calabi-Yau threefolds with compatible involutions. Such orientifolds are shown to lift to M-Theory on twisted connected sum \(G_2\) manifolds. Beautifully, the two building blocks forming the \(G_2\) manifold correspond to the open and closed string sectors. As an application, we show how to use such lifts to explicitly study open string moduli. Finally, we use our analysis to construct examples of \(G_2\) manifolds with different inequivalent TCS realizations.Quasinormal modes in charged fluids at complex momentum.https://www.zbmath.org/1456.830432021-04-16T16:22:00+00:00"Jansen, Aron"https://www.zbmath.org/authors/?q=ai:jansen.aron"Pantelidou, Christiana"https://www.zbmath.org/authors/?q=ai:pantelidou.christianaSummary: We investigate the convergence of relativistic hydrodynamics in charged fluids, within the framework of holography. On the one hand, we consider the analyticity properties of the dispersion relations of the hydrodynamic modes on the complex frequency and momentum plane and on the other hand, we perform a perturbative expansion of the dispersion relations in small momenta to a very high order. We see that the locations of the branch points extracted using the first approach are in good quantitative agreement with the radius of convergence extracted perturbatively. We see that for different values of the charge, different types of pole collisions set the radius of convergence. The latter turns out to be finite in the neutral case for all hydrodynamic modes, while it goes to zero at extremality for the shear and sound modes. Furthermore, we also establish the phenomenon of pole-skipping for the Reissner-Nordström black hole, and we find that the value of the momentum for which this phenomenon occurs need not be within the radius of convergence of hydrodynamics.Static cosmic strings in space-time with torsion, and strings with electromagnetism.https://www.zbmath.org/1456.830522021-04-16T16:22:00+00:00"Hammond, Richard T."https://www.zbmath.org/authors/?q=ai:hammond.richard-tThe effects of the dark energy on the static Schrödinger-Newton system -- an Adomian decomposition method and Padé approximants based approach.https://www.zbmath.org/1456.814582021-04-16T16:22:00+00:00"Mak, Man Kwong"https://www.zbmath.org/authors/?q=ai:mak.man-kwong"Leung, Chun Sing"https://www.zbmath.org/authors/?q=ai:leung.chun-sing"Harko, Tiberiu"https://www.zbmath.org/authors/?q=ai:harko.tiberiuOn fractional and fractal Einstein's field equations.https://www.zbmath.org/1456.830062021-04-16T16:22:00+00:00"El-Nabulsi, Rami Ahmad"https://www.zbmath.org/authors/?q=ai:el-nabulsi.rami-ahmad"Golmankhaneh, Alireza Khalili"https://www.zbmath.org/authors/?q=ai:golmankhaneh.alireza-khaliliSpherically symmetric AdS black holes with smeared mass distribution.https://www.zbmath.org/1456.830462021-04-16T16:22:00+00:00"Mourad, M. F."https://www.zbmath.org/authors/?q=ai:mourad.mohamed-f"Abdelgaber, M."https://www.zbmath.org/authors/?q=ai:abdelgaber.mAn analytical anisotropic compact stellar model of embedding class I.https://www.zbmath.org/1456.850022021-04-16T16:22:00+00:00"Baskey, Lipi"https://www.zbmath.org/authors/?q=ai:baskey.lipi"Das, Shyam"https://www.zbmath.org/authors/?q=ai:das.shyam"Rahaman, Farook"https://www.zbmath.org/authors/?q=ai:rahaman.farookA microscopic, non-equilibrium, statistical field theory for cosmic structure formation.https://www.zbmath.org/1456.850012021-04-16T16:22:00+00:00"Bartelmann, Matthias"https://www.zbmath.org/authors/?q=ai:bartelmann.matthias"Fabis, Felix"https://www.zbmath.org/authors/?q=ai:fabis.felix"Berg, Daniel"https://www.zbmath.org/authors/?q=ai:berg.daniel"Kozlikin, Elena"https://www.zbmath.org/authors/?q=ai:kozlikin.elena"Lilow, Robert"https://www.zbmath.org/authors/?q=ai:lilow.robert"Viermann, Celia"https://www.zbmath.org/authors/?q=ai:viermann.celiaLongitudinal Doppler effect in de Sitter expanding universe.https://www.zbmath.org/1456.830022021-04-16T16:22:00+00:00"Cotăescu, Ion I."https://www.zbmath.org/authors/?q=ai:cotaescu.ion-i-jun|cotaescu.ion-iApparent superluminal velocities and random walk in the velocity space.https://www.zbmath.org/1456.830052021-04-16T16:22:00+00:00"Sen, Abhijit"https://www.zbmath.org/authors/?q=ai:sen.abhijit"Silagadze, Zurab K."https://www.zbmath.org/authors/?q=ai:silagadze.zurab-kKink-antikink scattering-induced breathing bound states and oscillons in a parametrized \(\phi^4\) model.https://www.zbmath.org/1456.831222021-04-16T16:22:00+00:00"Nzoupe, F. Naha"https://www.zbmath.org/authors/?q=ai:nzoupe.f-naha"Dikandé, Alain M."https://www.zbmath.org/authors/?q=ai:dikande.alain-moise"Tchawoua, C."https://www.zbmath.org/authors/?q=ai:tchawoua.clementExplicit formula and meromorphic extension of the resolvent for the massive Dirac operator in the Schwarzschild-anti-de Sitter spacetime.https://www.zbmath.org/1456.811702021-04-16T16:22:00+00:00"Idelon-Riton, Guillaume"https://www.zbmath.org/authors/?q=ai:idelon-riton.guillaumeSummary: We study the resolvent of the massive Dirac operator in the Schwarzschild-anti-de Sitter space-time. After separation of variables, we use standard one-dimensional techniques to obtain an explicit formula. We then make use of this formula to extend the resolvent meromorphically across the real axis.{
\copyright 2017 American Institute of Physics}Influence of dark matter on phase transitions of XCDM black hole in Braneworld based on the framework of GUP.https://www.zbmath.org/1456.830372021-04-16T16:22:00+00:00"Liu, Xiang"https://www.zbmath.org/authors/?q=ai:liu.xiang"Li, Hui-Ling"https://www.zbmath.org/authors/?q=ai:li.huiling"Li, Liu"https://www.zbmath.org/authors/?q=ai:li.liuLorentz invariance violation and modified Hawking fermions tunneling radiation of stationary axially symmetric black holes.https://www.zbmath.org/1456.830452021-04-16T16:22:00+00:00"Luo, Z."https://www.zbmath.org/authors/?q=ai:luo.zhongjie|luo.zongdui|luo.zhangjie|luo.zhihong|luo.zhenhuang|luo.zhikun|luo.ziqiang|luo.zijian|luo.zewei|luo.zi-ping|luo.zhaofu|luo.zhengyuan|luo.zhijun|luo.zongyang|luo.zheng|luo.zhaoxia|luo.zhongyang|luo.zhilin|luo.zhaohua|luo.zhangtao|luo.zhenwei|luo.zhangkai|luo.zhaoyang|luo.zeyu|luo.zhikang|luo.zhibo|luo.zhenghua|luo.zhaohui|luo.ziwei|luo.zhihuan|luo.zhiliang|luo.zhao|luo.zhicheng|luo.zhaoming|luo.zhusan|luo.zhiwen|luo.zhonghua|luo.zhe|luo.zhongxian|luo.zhiguo|luo.zhiwei|luo.zhenjiang|luo.zhongwen|luo.zhengxuan|luo.zongfu|luo.zhiming|luo.zhipeng|luo.zuojuan|luo.zhongqiang|luo.zhongling|luo.zhifan|luo.zuying|luo.zhenbi|luo.zhongliang|luo.zhenou|luo.zhigang|luo.zhongxiang|luo.zhongde|luo.zhengming|luo.zhendong|luo.zujun|luo.zhongxuan|luo.zhong|luo.ziyan|luo.zhigo|luo.zhixue|luo.zhuangchu|luo.zuwen|luo.zhukai|luo.zhenjun|luo.zhi-quan|luo.zhengdong|luo.zhenhua|luo.zhiyong|luo.zhuhua|luo.zhehui|luo.zhifeng|luo.zhanghua|luo.zhiyuan|luo.zhijiang|luo.zuhua|luo.zhizeng|luo.zhonghui|luo.zhaonan|luo.zongwei|luo.zhensheng|luo.zongjun|luo.zhengxiang|luo.zhehu|luo.zhijian|luo.zhimin|luo.zunli|luo.zhenguo|luo.zhimeng|luo.zhihua|luo.zhixing|luo.zudao|luo.zhiqiang|luo.zhanhai|luo.zhen|luo.zhengqin|luo.zeju"Nie, W. F."https://www.zbmath.org/authors/?q=ai:nie.weifang"Feng, Y. Y."https://www.zbmath.org/authors/?q=ai:feng.youyi|feng.yayuan|feng.youyong|feng.yiying|feng.yuying|feng.yingying|feng.yuyu|feng.yanying|feng.yiyong|feng.yangyue|feng.yuanyue|feng.yuyou|feng.yaoyao|feng.yanyan|feng.yunyun|feng.yuanyuan|feng.yangyang"Lan, X. G."https://www.zbmath.org/authors/?q=ai:lan.xiao-gang|lan.xuguangSpin-0 scalar particle interacts with scalar potential in the presence of magnetic field and quantum flux under the effects of KKT in 5D cosmic string spacetime.https://www.zbmath.org/1456.812592021-04-16T16:22:00+00:00"Ahmed, Faizuddin"https://www.zbmath.org/authors/?q=ai:ahmed.faizuddinGravitational waves in the spinor theory of gravity.https://www.zbmath.org/1456.830502021-04-16T16:22:00+00:00"Novello, M."https://www.zbmath.org/authors/?q=ai:novello.mario|novello.marco"Hartmann, A. E. S."https://www.zbmath.org/authors/?q=ai:hartmann.a-e-sBTZ one-loop determinants via the Selberg zeta function for general spin.https://www.zbmath.org/1456.830662021-04-16T16:22:00+00:00"Keeler, Cynthia"https://www.zbmath.org/authors/?q=ai:keeler.cynthia-a"Martin, Victoria L."https://www.zbmath.org/authors/?q=ai:martin.victoria-l"Svesko, Andrew"https://www.zbmath.org/authors/?q=ai:svesko.andrewSummary: We relate the heat kernel and quasinormal mode methods of computing the 1-loop partition function of arbitrary spin fields on a rotating (Euclidean) BTZ background using the Selberg zeta function associated with \(\mathbb{H}^3/\mathbb{Z}\), extending our work [``Connecting quasinormal modes and heat kernels in 1-loop determinants'', SciPost Phys. 8, No. 2, 017, 22 p. (2020; \url{doi:10.21468/SciPostPhys.8.2.017})]. Previously, \textit{P. A. Perry} and \textit{F. L. Williams} [Int. J. Pure Appl. Math. 9, No. 1, 1--21 (2003; Zbl 1056.11030)] showed for a scalar field that the zeros of the Selberg zeta function coincide with the poles of the associated scattering operator upon a relabeling of integers. We extend the integer relabeling to the case of general spin, and discuss its relationship to the removal of non-square-integrable Euclidean zero modes.Duality and supersymmetry constraints on the weak gravity conjecture.https://www.zbmath.org/1456.830112021-04-16T16:22:00+00:00"Loges, Gregory J."https://www.zbmath.org/authors/?q=ai:loges.gregory-j"Noumi, Toshifumi"https://www.zbmath.org/authors/?q=ai:noumi.toshifumi"Shiu, Gary"https://www.zbmath.org/authors/?q=ai:shiu.garySummary: Positivity bounds coming from consistency of UV scattering amplitudes are not always sufficient to prove the weak gravity conjecture for theories beyond Einstein-Maxwell. Additional ingredients about the UV may be necessary to exclude those regions of parameter space which are naïvely in conflict with the predictions of the weak gravity conjecture. In this paper we explore the consequences of imposing additional symmetries inherited from the UV theory on higher-derivative operators for Einstein-Maxwell-dilaton-axion theory. Using black hole thermodynamics, for a preserved \( \mathrm{SL}(2, \mathbb{R})\) symmetry we find that the weak gravity conjecture then does follow from positivity bounds. For a preserved \( \mathrm{O}( d, d; \mathbb{R})\) symmetry we find a simple condition on the two Wilson coefficients which ensures the positivity of corrections to the charge-to-mass ratio and that follows from the null energy condition alone. We find that imposing supersymmetry on top of either of these symmetries gives corrections which vanish identically, as expected for BPS states.Asymptotic completeness for superradiant Klein-Gordon equations and applications to the de Sitter-Kerr metric.https://www.zbmath.org/1456.351222021-04-16T16:22:00+00:00"Georgescu, Vladimir"https://www.zbmath.org/authors/?q=ai:georgescu.vladimir"Gérard, Christian"https://www.zbmath.org/authors/?q=ai:gerard.christian"Häfner, Dietrich"https://www.zbmath.org/authors/?q=ai:hafner.dietrichSummary: We show asymptotic completeness for a class of superradiant Klein-Gordon equations. Our results are applied to the Klein-Gordon equation on the De Sitter-Kerr metric with small angular momentum of the black hole. For this equation we obtain asymptotic completeness for fixed angular momentum of the field.A one parameter family of Calabi-Yau manifolds with attractor points of rank two.https://www.zbmath.org/1456.830892021-04-16T16:22:00+00:00"Candelas, Philip"https://www.zbmath.org/authors/?q=ai:candelas.philip"de la Ossa, Xenia"https://www.zbmath.org/authors/?q=ai:de-la-ossa.xenia-c"Elmi, Mohamed"https://www.zbmath.org/authors/?q=ai:elmi.mohamed"van Straten, Duco"https://www.zbmath.org/authors/?q=ai:van-straten.ducoSummary: In the process of studying the \(\zeta\)-function for one parameter families of Calabi-Yau manifolds we have been led to a manifold, first studied by Verrill, for which the quartic numerator of the \(\zeta\)-function factorises into two quadrics remarkably often. Among these factorisations, we find \textit{persistent factorisations}; these are determined by a parameter that satisfies an algebraic equation with coefficients in \(\mathbb{Q}\), so independent of any particular prime. Such factorisations are expected to be modular with each quadratic factor associated to a modular form. If the parameter is defined over \(\mathbb{Q}\) this modularity is assured by the proof of the Serre Conjecture. We identify three values of the parameter that give rise to persistent factorisations, one of which is defined over \(\mathbb{Q}\), and identify, for all three cases, the associated modular groups. We note that these factorisations are due a splitting of Hodge structure and that these special values of the parameter are rank two attractor points in the sense of IIB supergravity. To our knowledge, these points provide the first explicit examples of non-singular, non-rigid rank two attractor points for Calabi-Yau manifolds of full SU(3) holonomy. The values of the periods and their covariant derivatives, at the attractor points, are identified in terms of critical values of the \(L\)-functions of the modular groups. Thus the critical \(L\)-values enter into the calculation of physical quantities such as the area of the black hole in the 4D spacetime. In our search for additional rank two attractor points, we perform a statistical analysis of the numerator of the \(\zeta\)-function and are led to conjecture that the coefficients in this polynomial are distributed according to the statistics of random USp(4) matrices.Curvature properties of \((t-z)\)-type plane wave metric.https://www.zbmath.org/1456.530172021-04-16T16:22:00+00:00"Eyasmin, Sabina"https://www.zbmath.org/authors/?q=ai:eyasmin.sabina"Chakraborty, Dhyanesh"https://www.zbmath.org/authors/?q=ai:chakraborty.dhyaneshSummary: The objective, in this paper, is to obtain the curvature properties of \((t-z)\)-type plane wave metric studied by Bondi et al. (1959). For this a general \(( t - z )\)-type wave metric is considered and the condition for which it obeys Einstein's empty spacetime field equations is obtained. It is found that the rank of the Ricci tensor of \((t-z)\)-type plane wave metric is 1 and is of Codazzi type. Also it is proved that it is not recurrent but Ricci recurrent, conformally recurrent and hyper generalized recurrent. Moreover, it is semisymmetric and satisfies the Ricci generalized pseudosymmetric type condition \(P\cdot P=-\frac{1}{3} Q(Ric,P)\). It is interesting to note that, physically, the energy momentum tensor describes a radiation field with parallel rays and geometrically it is a Codazzi tensor and semisymmetric. As special case, the geometric structures of Taub's plane symmetric spacetime metric are deduced. Comparisons between \((t-z)\)-type plane wave metric and pp-wave metric with respect to their geometric structures are viewed.Dressing bulk fields in \(\mathrm{AdS}_3\).https://www.zbmath.org/1456.830272021-04-16T16:22:00+00:00"Kabat, Daniel"https://www.zbmath.org/authors/?q=ai:kabat.daniel"Lifschytz, Gilad"https://www.zbmath.org/authors/?q=ai:lifschytz.giladSummary: We study a set of CFT operators suitable for reconstructing a charged bulk scalar field \(\varphi\) in \(\mathrm{AdS}_3\) (dual to an operator \(\mathcal{O}\) of dimension \(\Delta\) in the CFT) in the presence of a conserved spin-\(n\) current in the CFT. One has to sum a tower of smeared non-primary scalars \({\partial}_+^m{J}^{(m)}\), where \(J^{(m)}\) are primaries with twist \(\Delta\) and spin \(m\) built from \(\mathcal{O}\) and the current. The coefficients of these operators can be fixed by demanding that bulk correlators are well-defined: with a simple ansatz this requirement allows us to calculate bulk correlators directly from the CFT. They are built from specific polynomials of the kinematic invariants up to a freedom to make field redefinitions. To order \(1/N\) this procedure captures the dressing of the bulk scalar field by a radial generalized Wilson line.Quantum spacetime and the universe at the big bang, vanishing interactions and fading degrees of freedom.https://www.zbmath.org/1456.814472021-04-16T16:22:00+00:00"Doplicher, Sergio"https://www.zbmath.org/authors/?q=ai:doplicher.sergio"Morsella, Gerardo"https://www.zbmath.org/authors/?q=ai:morsella.gerardo"Pinamonti, Nicola"https://www.zbmath.org/authors/?q=ai:pinamonti.nicolaSummary: As discussed in \textit{D. Bahns}, the 1st author et al. [Brunetti, Romeo (ed.) et al., Advances in algebraic quantum field theory. Cham: Springer (ISBN 978-3-319-21352-1/hbk; 978-3-319-21353-8/ebook). Mathematical Physics Studies, 289-329 (2015; Zbl 1334.81078)] fundamental physical principles suggests that, close to cosmological singularities, the effective Planck length diverges, hence a ``quantum point'' becomes infinitely extended. We argue that, as a consequence, at the origin of times spacetime might reduce effectively to a single point and interactions disappear. This conclusion is supported by converging evidences in two different approaches to interacting quantum fields on Quantum Spacetime: (1) as the Planck length diverges, the field operators evaluated at a ``quantum point'' converge to zero, and so do the lowest order expressions for interacting fields in the Yang Feldman approach; (2) in the same limit, we find convergence of the interacting vacuum to the free one at all perturbative orders. The latter result is obtained using the adaptation, performed in the 1st author et al. [Commun. Math. Phys. 379, No. 3, 1035-1076 (2020; Zbl 07263743)], of the methods of perturbative Algebraic Quantum Field Theory to Quantum Spacetime, through a novel picture of the effective Lagrangian, which maintains the ultraviolet finiteness of the perturbation expansion and allows one to prove also the existence of the adiabatic limit. It remains an open question whether the \(S\) matrix itself converges to unity and whether the limit in which the effective Planck length diverges is a unique initial condition or an unreachable limit, and only different asymptotics matter.Averaging over Narain moduli space.https://www.zbmath.org/1456.830672021-04-16T16:22:00+00:00"Maloney, Alexander"https://www.zbmath.org/authors/?q=ai:maloney.alexander"Witten, Edward"https://www.zbmath.org/authors/?q=ai:witten.edwardSummary: Recent developments involving JT gravity in two dimensions indicate that under some conditions, a gravitational path integral is dual to an average over an ensemble of boundary theories, rather than to a specific boundary theory. For an example in one dimension more, one would like to compare a random ensemble of two-dimensional CFT's to Einstein gravity in three dimensions. But this is difficult. For a simpler problem, here we average over Narain's family of two-dimensional CFT's obtained by toroidal compactification. These theories are believed to be the most general ones with their central charges and abelian current algebra symmetries, so averaging over them means picking a random CFT with those properties. The average can be computed using the Siegel-Weil formula of number theory and has some properties suggestive of a bulk dual theory that would be an exotic theory of gravity in three dimensions. The bulk dual theory would be more like \(\mathrm{U}(1)^{2D}\) Chern-Simons theory than like Einstein gravity.Dyonic black hole degeneracies in \(\mathcal{N} = 4\) string theory from Dabholkar-Harvey degeneracies.https://www.zbmath.org/1456.830392021-04-16T16:22:00+00:00"Chowdhury, Abhishek"https://www.zbmath.org/authors/?q=ai:chowdhury.abhishek"Kidambi, Abhiram"https://www.zbmath.org/authors/?q=ai:kidambi.abhiram"Murthy, Sameer"https://www.zbmath.org/authors/?q=ai:murthy.sameer"Reys, Valentin"https://www.zbmath.org/authors/?q=ai:reys.valentin"Wrase, Timm"https://www.zbmath.org/authors/?q=ai:wrase.timmSummary: The degeneracies of single-centered dyonic \(\frac{1}{4}\)-BPS black holes (BH) in Type II string theory on \(K3 \times T^2\) are known to be coefficients of certain mock Jacobi forms arising from the Igusa cusp form \(\Phi_{10}\). In this paper we present an exact analytic formula for these BH degeneracies purely in terms of the degeneracies of the perturbative \(\frac{1}{2}\)-BPS states of the theory. We use the fact that the degeneracies are completely controlled by the polar coefficients of the mock Jacobi forms, using the Hardy-Ramanujan-Rademacher circle method. Here we present a simple formula for these polar coefficients as a quadratic function of the \(\frac{1}{2}\)-BPS degeneracies. We arrive at the formula by using the physical interpretation of polar coefficients as negative discriminant states, and then making use of previous results in the literature to track the decay of such states into pairs of \(\frac{1}{2}\)-BPS states in the moduli space. Although there are an infinite number of such decays, we show that only a finite number of them contribute to the formula. The phenomenon of BH bound state metamorphosis (BSM) plays a crucial role in our analysis. We show that the dyonic BSM orbits with \(U\)-duality invariant \(\Delta < 0\) are in exact correspondence with the solution sets of the Brahmagupta-Pell equation, which implies that they are isomorphic to the group of units in the order \(\mathbb{Z} [ \sqrt{\left|\Delta \right|} ]\) in the real quadratic field \(\mathbb{Q} ( \sqrt{\left|\Delta \right|})\). We check our formula against the known numerical data arising from the Igusa cusp form, for the first 1650 polar coefficients, and find perfect agreement.Gravitational waves carrying orbital angular momentum.https://www.zbmath.org/1456.830122021-04-16T16:22:00+00:00"Bialynicki-Birula, Iwo"https://www.zbmath.org/authors/?q=ai:bialynicki-birula.iwo"Bialynicka-Birula, Zofia"https://www.zbmath.org/authors/?q=ai:bialynicka-birula.zofiaEinstein-Cartan gravity, matter, and scale-invariant generalization.https://www.zbmath.org/1456.830702021-04-16T16:22:00+00:00"Shaposhnikov, M."https://www.zbmath.org/authors/?q=ai:shaposhnikov.mikhail"Shkerin, A."https://www.zbmath.org/authors/?q=ai:shkerin.andrey"Timiryasov, I."https://www.zbmath.org/authors/?q=ai:timiryasov.i"Zell, S."https://www.zbmath.org/authors/?q=ai:zell.sebastianSummary: We study gravity coupled to scalar and fermion fields in the Einstein-Cartan framework. We discuss the most general form of the action that contains terms of mass dimension not bigger than four, leaving out only contributions quadratic in curvature. By resolving the theory explicitly for torsion, we arrive at an equivalent metric theory containing additional six-dimensional operators. This lays the groundwork for cosmological studies of the theory. We also perform the same analysis for a no-scale scenario in which the Planck mass is eliminated at the cost of adding an extra scalar degree of freedom. Finally, we outline phenomenological implications of the resulting theories, in particular to inflation and dark matter production.On a gravity dual to flavored topological quantum mechanics.https://www.zbmath.org/1456.830632021-04-16T16:22:00+00:00"Feldman, Andrey"https://www.zbmath.org/authors/?q=ai:feldman.andreySummary: In this paper, we propose a generalization of the \(\mathrm{AdS}_2/\mathrm{CFT}_1\) correspondence constructed by \textit{M. Mezei} in [``A 2d/1d holographic duality'', Preprint, \url{arXiv:1703.08749}], which is the duality between 2d Yang-Mills theory with higher derivatives in the \(\mathrm{AdS}_2\) background, and 1d topological quantum mechanics of two adjoint and two fundamental \(\mathrm{U}(N)\) fields, governing certain protected sector of operators in 3d ABJM theory at the Chern-Simons level \(k = 1\). We construct a holographic dual to a flavored generalization of the 1d quantum mechanics considered in [loc. cit.], which arises as the effective field theory living on the intersection of stacks of \(N\) D2-branes and \(k\) D6-branes in the \(\Omega\)-background in Type IIA string theory, and describes the dynamics of the protected sector of operators in \(\mathcal{N} = 4\) theory with \(k\) fundamental hypermultiplets, having a holographic description as M-theory in the \(\mathrm{AdS}_4 \times S^7/ \mathbb{Z}_k\) background. We compute the structure constants of the bulk theory gauge group, and construct a map between the observables of the boundary theory and the fields of the bulk theory.Quantum extremal islands made easy. I: Entanglement on the brane.https://www.zbmath.org/1456.813322021-04-16T16:22:00+00:00"Chen, Hong Zhe"https://www.zbmath.org/authors/?q=ai:chen.hong-zhe"Myers, Robert C."https://www.zbmath.org/authors/?q=ai:myers.robert-c"Neuenfeld, Dominik"https://www.zbmath.org/authors/?q=ai:neuenfeld.dominik"Reyes, Ignacio A."https://www.zbmath.org/authors/?q=ai:reyes.ignacio-a"Sandor, Joshua"https://www.zbmath.org/authors/?q=ai:sandor.joshuaSummary: Recent progress in our understanding of the black hole information paradox has lead to a new prescription for calculating entanglement entropies, which involves special subsystems in regions where gravity is dynamical, called \textit{quantum extremal islands}. We present a simple holographic framework where the emergence of quantum extremal islands can be understood in terms of the standard Ryu-Takayanagi prescription, used for calculating entanglement entropies in the boundary theory. Our setup describes a \(d\)-dimensional boundary CFT coupled to a \((d -1)\)-dimensional defect, which are dual to global \(\mathrm{AdS}_{d+1}\) containing a codimension-one brane. Through the Randall-Sundrum mechanism, graviton modes become localized at the brane, and in a certain parameter regime, an effective description of the brane is given by Einstein gravity on an \(\mathrm{AdS}_d\) background coupled to two copies of the boundary CFT. Within this effective description, the standard RT formula implies the existence of quantum extremal islands in the gravitating region, whenever the RT surface crosses the brane. This indicates that islands are a universal feature of effective theories of gravity and need not be tied to the presence of black holes.Swampland constraints on no-boundary quantum cosmology.https://www.zbmath.org/1456.831212021-04-16T16:22:00+00:00"Matsui, Hiroki"https://www.zbmath.org/authors/?q=ai:matsui.hiroki"Terada, Takahiro"https://www.zbmath.org/authors/?q=ai:terada.takahiroSummary: The Hartle-Hawking no-boundary proposal describes the quantum creation of the universe. To have a non-negligible probability to obtain a classical expanding universe, eternal inflation is required, which is severely constrained by Swampland conjectures such as the refined de Sitter conjecture and the distance conjecture. We discuss this issue in detail and demonstrate the incompatibility. We show that the dimensionless parameters in the refined de Sitter conjecture should be bounded from above by a positive power of the scalar potential to realize the classical expanding universe. In other words, the probability of the classical expanding universe is extremely small under the Swampland conjectures unless the parameters are much smaller than unity. If they are order unity, on the other hand, the saddle-point solution itself ceases to exist implying a genuinely quantum universe.JT supergravity and Brezin-Gross-Witten tau-function.https://www.zbmath.org/1456.831162021-04-16T16:22:00+00:00"Okuyama, Kazumi"https://www.zbmath.org/authors/?q=ai:okuyama.kazumi"Sakai, Kazuhiro"https://www.zbmath.org/authors/?q=ai:sakai.kazuhiroSummary: We study thermal correlation functions of Jackiw-Teitelboim (JT) supergravity. We focus on the case of JT supergravity on orientable surfaces without time-reversal symmetry. As shown by Stanford and Witten recently, the path integral amounts to the computation of the volume of the moduli space of super Riemann surfaces, which is characterized by the Brezin-Gross-Witten (BGW) tau-function of the KdV hierarchy. We find that the matrix model of JT supergravity is a special case of the BGW model with infinite number of couplings turned on in a specific way, by analogy with the relation between bosonic JT gravity and the Kontsevich-Witten (KW) model. We compute the genus expansion of the one-point function of JT supergravity and study its low-temperature behavior. In particular, we propose a non-perturbative completion of the one-point function in the Bessel case where all couplings in the BGW model are set to zero. We also investigate the free energy and correlators when the Ramond-Ramond flux is large. We find that by defining a suitable basis higher genus free energies are written exactly in the same form as those of the KW model, up to the constant terms coming from the volume of the unitary group. This implies that the constitutive relation of the KW model is universal to the tau-function of the KdV hierarchy.Covert symmetry breaking.https://www.zbmath.org/1456.813332021-04-16T16:22:00+00:00"Erickson, C. W."https://www.zbmath.org/authors/?q=ai:erickson.c-w"Harrold, A. D."https://www.zbmath.org/authors/?q=ai:harrold.a-d"Leung, Rahim"https://www.zbmath.org/authors/?q=ai:leung.rahim"Stelle, K. S."https://www.zbmath.org/authors/?q=ai:stelle.kellogg-sSummary: Reduction from a higher-dimensional to a lower-dimensional field theory can display special features when the zero-level ground state has nontrivial dependence on the reduction coordinates. In particular, a delayed `covert' form of spontaneous symmetry breaking can occur, revealing itself only at fourth order in the lower-dimensional effective field theory action. This phenomenon is explored in a simple model of \((d + 1)\)-dimensional scalar QED with one dimension restricted to an interval with Dirichlet/Robin boundary conditions on opposing ends. This produces an effective \(d\)-dimensional theory with Maxwellian dynamics at the free theory level, but with unusual symmetry breaking appearing in the quartic vector-scalar interaction terms. This simple model is chosen to illuminate the mechanism of effects which are also noted in gravitational braneworld scenarios.Spectral theories and topological strings on del Pezzo geometries.https://www.zbmath.org/1456.831062021-04-16T16:22:00+00:00"Moriyama, Sanefumi"https://www.zbmath.org/authors/?q=ai:moriyama.sanefumiSummary: Motivated by understanding M2-branes, we propose to reformulate partition functions of M2-branes by quantum curves. Especially, we focus on the backgrounds of \textit{P. del Pezzo} [Nap. Rend. 24, 212--216 (1885; JFM 17.0514.01)] geometries, which enjoy Weyl group symmetries of exceptional algebras. We construct quantum curves explicitly and turn to the analysis of classical phase space areas and quantum mirror maps. We find that the group structure helps in clarifying previous subtleties, such as the shift of the chemical potential in the area and the identification of the overall factor of the spectral operator in the mirror map. We list the multiplicities characterizing the quantum mirror maps and find that the decoupling relation known for the BPS indices works for the mirror maps. As a result, with the group structure we can present explicitly the statement for the correspondence between spectral theories and topological strings on del Pezzo geometries.Strong coupling expansion of circular Wilson loops and string theories in \(\mathrm{AdS}_5 \times S^5\) and \(\mathrm{AdS}_4 \times CP^3\).https://www.zbmath.org/1456.831002021-04-16T16:22:00+00:00"Giombi, Simone"https://www.zbmath.org/authors/?q=ai:giombi.simone"Tseytlin, Arkady A."https://www.zbmath.org/authors/?q=ai:tseytlin.arkady-aSummary: We revisit the problem of matching the strong coupling expansion of the \(\frac{1}{2}\) BPS circular Wilson loops in \(\mathcal{N} = 4\) SYM and ABJM gauge theories with their string theory duals in \(\mathrm{AdS}_5 \times S^5\) and \(\mathrm{AdS}_4 \times CP^3\), at the first subleading (one-loop) order of the expansion around the minimal surface. We observe that, including the overall factor \(1/g_s\) of the inverse string coupling constant, as appropriate for the open string partition function with disk topology, and a universal prefactor proportional to the square root of the string tension \(T\), both the SYM and ABJM results precisely match the string theory prediction. We provide an explanation of the origin of the \(\sqrt{T}\) prefactor based on special features of the combination of one-loop determinants appearing in the string partition function. The latter also implies a natural generalization \(Z_\chi \sim ( \sqrt{T}/{g}_{s} )^\chi\) to higher genus contributions with the Euler number \(\chi\), which is consistent with the structure of the \(1/N\) corrections found on the gauge theory side.Mimetic Einstein-Cartan-Sciama-Kibble (ECSK) gravity.https://www.zbmath.org/1456.830652021-04-16T16:22:00+00:00"Izaurieta, Fernando"https://www.zbmath.org/authors/?q=ai:izaurieta.fernando"Medina, Perla"https://www.zbmath.org/authors/?q=ai:medina.perla"Merino, Nelson"https://www.zbmath.org/authors/?q=ai:merino.nelson"Salgado, Patricio"https://www.zbmath.org/authors/?q=ai:salgado.patricio"Valdivia, Omar"https://www.zbmath.org/authors/?q=ai:valdivia.omarSummary: In this paper, we formulate the Mimetic theory of gravity in first-order formalism for differential forms, i.e., the mimetic version of Einstein-Cartan-Sciama-Kibble (ECSK) gravity. We consider different possibilities on how torsion is affected by Weyl transformations and discuss how this translates into the interpolation between two different Weyl transformations of the spin connection, parameterized with a zero-form parameter \(\lambda\). We prove that regardless of the type of transformation one chooses, in this setting torsion remains as a non-propagating field. We also discuss the conservation of the mimetic stress-energy tensor and show that the trace of the total stress-energy tensor is not null but depends on both, the value of \(\lambda\) and spacetime torsion.\(\mathcal{N} = 1\) supersymmetric double field theory and the generalized Kerr-Schild ansatz.https://www.zbmath.org/1456.830072021-04-16T16:22:00+00:00"Lescano, Eric"https://www.zbmath.org/authors/?q=ai:lescano.eric"Rodríguez, Jesús A."https://www.zbmath.org/authors/?q=ai:rodriguez.jesus-aSummary: We construct the \(\mathcal{N} = 1\) supersymmetric extension of the generalized Kerr-Schild ansatz in the flux formulation of Double Field Theory. We show that this ansatz is compatible with \(\mathcal{N} = 1\) supersymmetry as long as it is not written in terms of generalized null vectors. Supersymmetric consistency is obtained through a set of conditions that imply linearity of the generalized gravitino perturbation and unrestricted perturbations of the generalized background dilaton and dilatino. As a final step we parametrize the previous theory in terms of the field content of the low energy effective 10-dimensional heterotic supergravity and we find that the perturbation of the 10-dimensional vielbein, Kalb-Ramond field, gauge field, gravitino and gaugino can be written in terms of vectors, as expected.Gauged sigma-models with nonclosed 3-form and twisted Jacobi structures.https://www.zbmath.org/1456.814062021-04-16T16:22:00+00:00"Chatzistavrakidis, Athanasios"https://www.zbmath.org/authors/?q=ai:chatzistavrakidis.athanasios"Šimunić, Grgur"https://www.zbmath.org/authors/?q=ai:simunic.grgurSummary: We study aspects of two-dimensional nonlinear sigma models with Wess-Zumino term corresponding to a nonclosed 3-form, which may arise upon dimensional reduction in the target space. Our goal in this paper is twofold. In a first part, we investigate the conditions for consistent gauging of sigma models in the presence of a nonclosed 3-form. In the abelian case, we find that the target of the gauged theory has the structure of a contact Courant algebroid, twisted by a 3-form and two 2-forms. Gauge invariance constrains the theory to (small) Dirac structures of the contact Courant algebroid. In the non-abelian case, we draw a similar parallel between the gauged sigma model and certain transitive Courant algebroids and their corresponding Dirac structures. In the second part of the paper, we study two-dimensional sigma models related to Jacobi structures. The latter generalise Poisson and contact geometry in the presence of an additional vector field. We demonstrate that one can construct a sigma model whose gauge symmetry is controlled by a Jacobi structure, and moreover we twist the model by a 3-form. This construction is then the analogue of WZW-Poisson structures for Jacobi manifolds.A Monte Carlo approach to the worldline formalism in curved space.https://www.zbmath.org/1456.812942021-04-16T16:22:00+00:00"Corradini, Olindo"https://www.zbmath.org/authors/?q=ai:corradini.olindo"Muratori, Maurizio"https://www.zbmath.org/authors/?q=ai:muratori.maurizioSummary: We present a numerical method to evaluate worldline (WL) path integrals defined on a curved Euclidean space, sampled with Monte Carlo (MC) techniques. In particular, we adopt an algorithm known as \textit{YLOOPS} with a slight modification due to the introduction of a quadratic term which has the function of stabilizing and speeding up the convergence. Our method, as the perturbative counterparts, treats the non-trivial measure and deviation of the kinetic term from flat, as interaction terms. Moreover, the numerical discretization adopted in the present WLMC is realized with respect to the proper time of the associated bosonic point-particle, hence such procedure may be seen as an analogue of the time-slicing (TS) discretization already introduced to construct quantum path integrals in curved space. As a result, a TS counter-term is taken into account during the computation. The method is tested against existing analytic calculations of the heat kernel for a free bosonic point-particle in a \(D\)-dimensional maximally symmetric space.Superconformal RG interfaces in holography.https://www.zbmath.org/1456.814202021-04-16T16:22:00+00:00"Arav, Igal"https://www.zbmath.org/authors/?q=ai:arav.igal"Cheung, K. C. Matthew"https://www.zbmath.org/authors/?q=ai:cheung.k-c-matthew"Gauntlett, Jerome P."https://www.zbmath.org/authors/?q=ai:gauntlett.jerome-p"Roberts, Matthew M."https://www.zbmath.org/authors/?q=ai:roberts.matthew-m"Rosen, Christopher"https://www.zbmath.org/authors/?q=ai:rosen.christopherSummary: We construct gravitational solutions that holographically describe two different \(d = 4\) SCFTs joined together at a co-dimension one, planar RG interface and preserving \(d = 3\) superconformal symmetry. The RG interface joins \(\mathcal{N} = 4\) SYM theory on one side with the \(\mathcal{N} = 1\) Leigh-Strassler SCFT on the other. We construct a family of such solutions, which in general are associated with spatially dependent mass deformations on the \(\mathcal{N} = 4\) SYM side, but there is a particular solution for which these deformations vanish. We also construct a Janus solution with the Leigh-Strassler SCFT on either side of the interface. Gravitational solutions associated with superconformal interfaces involving ABJM theory and two \(d = 3 \ \mathcal{N} = 1\) SCFTs with \(G_2\) symmetry are also discussed and shown to have similar properties, but they also exhibit some new features.Classical gravitational self-energy from double copy.https://www.zbmath.org/1456.830142021-04-16T16:22:00+00:00"Almeida, Gabriel Luz"https://www.zbmath.org/authors/?q=ai:almeida.gabriel-luz"Foffa, Stefano"https://www.zbmath.org/authors/?q=ai:foffa.stefano"Sturani, Riccardo"https://www.zbmath.org/authors/?q=ai:sturani.riccardoSummary: We apply the classical double copy to the calculation of self-energy of composite systems with multipolar coupling to gravitational field, obtaining next-to-leading order results in the gravitational coupling \(G_N\) by generalizing color to kinematics replacement rules known in literature. When applied to the multipolar description of the two-body system, the self-energy diagrams studied in this work correspond to tail processes, whose physical interpretation is of radiation being emitted by the non-relativistic source, scattered by the curvature generated by the binary system and then re-absorbed by the same source. These processes contribute to the conservative two-body dynamics and the present work represents a decisive step towards the systematic use of double copy within the multipolar post-Minkowskian expansion.Gravitational shock waves and scattering amplitudes.https://www.zbmath.org/1456.830132021-04-16T16:22:00+00:00"Cristofoli, Andrea"https://www.zbmath.org/authors/?q=ai:cristofoli.andreaSummary: We study gravitational shock waves using scattering amplitude techniques. After first reviewing the derivation in General Relativity as an ultrarelativistic boost of a Schwarzschild solution, we provide an alternative derivation by exploiting a novel relation between scattering amplitudes and solutions to Einstein field equations. We prove that gravitational shock waves arise from the classical part of a three point function with two massless scalars and a graviton. The region where radiation is localized has a distributional profile and it is now recovered in a natural way, thus bypassing the introduction of singular coordinate transformations as used in General Relativity. The computation is easily generalized to arbitrary dimensions and we show how the exactness of the classical solution follows from the absence of classical contributions at higher loops. A classical double copy between gravitational and electromagnetic shock waves is also provided and for a spinning source, using the exponential form of three point amplitudes, we infer a remarkable relation between gravitational shock waves and spinning ones, also known as gyratons. Using this property, we infer a family of exact solutions describing gravitational shock waves with spin. We then compute the phase shift of a particle in a background of shock waves finding agreement with an earlier computation by Amati, Ciafaloni and Veneziano for particles in the high energy limit. Applied to a gyraton, it provides a result for the scattering angle to all orders in spin.Scattering equations in AdS: scalar correlators in arbitrary dimensions.https://www.zbmath.org/1456.830962021-04-16T16:22:00+00:00"Eberhardt, Lorenz"https://www.zbmath.org/authors/?q=ai:eberhardt.lorenz"Komatsu, Shota"https://www.zbmath.org/authors/?q=ai:komatsu.shota"Mizera, Sebastian"https://www.zbmath.org/authors/?q=ai:mizera.sebastianSummary: We introduce a bosonic ambitwistor string theory in AdS space. Even though the theory is anomalous at the quantum level, one can nevertheless use it in the classical limit to derive a novel formula for correlation functions of boundary CFT operators in arbitrary space-time dimensions. The resulting construction can be treated as a natural extension of the CHY formalism for the flat-space S-matrix, as it similarly expresses tree-level amplitudes in AdS as integrals over the moduli space of Riemann spheres with punctures. These integrals localize on an operator-valued version of scattering equations, which we derive directly from the ambitwistor string action on a coset manifold. As a testing ground for this formalism we focus on the simplest case of ambitwistor string coupled to two current algebras, which gives bi-adjoint scalar correlators in AdS. In order to evaluate them directly, we make use of a series of contour deformations on the moduli space of punctured Riemann spheres and check that the result agrees with tree level Witten diagram computations to all multiplicity. We also initiate the study of eigenfunctions of scattering equations in AdS, which interpolate between conformal partial waves in different OPE channels, and point out a connection to an elliptic deformation of the Calogero-Sutherland model.A string theory realization of special unitary quivers in 3 dimensions.https://www.zbmath.org/1456.830942021-04-16T16:22:00+00:00"Collinucci, Andrés"https://www.zbmath.org/authors/?q=ai:collinucci.andres"Valandro, Roberto"https://www.zbmath.org/authors/?q=ai:valandro.robertoSummary: We propose a string theory realization of three-dimensional \(\mathcal{N} = 4\) quiver gauge theories with special unitary gauge groups. This is most easily understood in type IIA string theory with D4-branes wrapped on holomorphic curves in local K3's, by invoking the Stückelberg mechanism. From the type IIB perspective, this is understood as simply compactifying the familiar Hanany-Witten (HW) constructions on a \(T^3\). The mirror symmetry duals are easily derived. We illustrate this with various examples of mirror pairs.Spatially modulated and supersymmetric mass deformations of \(\mathcal{N} = 4\) SYM.https://www.zbmath.org/1456.831102021-04-16T16:22:00+00:00"Arav, Igal"https://www.zbmath.org/authors/?q=ai:arav.igal"Cheung, K. C. Matthew"https://www.zbmath.org/authors/?q=ai:cheung.k-c-matthew"Gauntlett, Jerome P."https://www.zbmath.org/authors/?q=ai:gauntlett.jerome-p"Roberts, Matthew M."https://www.zbmath.org/authors/?q=ai:roberts.matthew-m"Rosen, Christopher"https://www.zbmath.org/authors/?q=ai:rosen.christopherSummary: We study mass deformations of \(\mathcal{N} = 4, \ d = 4\) SYM theory that are spatially modulated in one spatial dimension and preserve some residual supersymmetry. We focus on generalisations of \(\mathcal{N} = 1^\ast\) theories and show that it is also possible, for suitably chosen supersymmetric masses, to preserve \(d = 3\) conformal symmetry associated with a co-dimension one interface. Holographic solutions can be constructed using \(D = 5\) theories of gravity that arise from consistent truncations of SO(6) gauged supergravity and hence type IIB supergravity. For the mass deformations that preserve \(d = 3\) superconformal symmetry we construct a rich set of Janus solutions of \(\mathcal{N} = 4\) SYM theory which have the same coupling constant on either side of the interface. Limiting classes of these solutions give rise to RG interface solutions with \(\mathcal{N} = 4\) SYM on one side of the interface and the Leigh-Strassler (LS) SCFT on the other, and also to a Janus solution for the LS theory. Another limiting solution is a new supersymmetric \( \mathrm{AdS}_4 \times S^1 \times S^5\) solution of type IIB supergravity.Reflected entropy for an evaporating black hole.https://www.zbmath.org/1456.830602021-04-16T16:22:00+00:00"Li, Tianyi"https://www.zbmath.org/authors/?q=ai:li.tianyi"Chu, Jinwei"https://www.zbmath.org/authors/?q=ai:chu.jinwei"Zhou, Yang"https://www.zbmath.org/authors/?q=ai:zhou.yangSummary: We study reflected entropy as a mixed state correlation measure in black hole evaporation. As a measure for bipartite mixed states, reflected entropy can be computed between black hole and radiation, radiation and radiation, and even black hole and black hole. We compute reflected entropy curves in three different models: 3-side wormhole model, End-of-the-World (EOW) brane model in three dimensions and two-dimensional eternal black hole plus CFT model. For 3-side wormhole model, we find that reflected entropy is dual to island cross section. The reflected entropy between radiation and black hole increases at early time and then decreases to zero, similar to Page curve, but with a later transition time. The reflected entropy between radiation and radiation first increases and then saturates. For the EOW brane model, similar behaviors of reflected entropy are found. We propose a quantum extremal surface for reflected entropy, which we call quantum extremal cross section. In the eternal black hole plus CFT model, we find a generalized formula for reflected entropy with island cross section as its area term by considering the right half as the canonical purification of the left. Interestingly, the reflected entropy curve between the left black hole and the left radiation is nothing but the Page curve. We also find that reflected entropy between the left black hole and the right black hole decreases and goes to zero at late time. The reflected entropy between radiation and radiation increases at early time and saturates at late time.Holographic spin liquids and Lovelock Chern-Simons gravity.https://www.zbmath.org/1456.830762021-04-16T16:22:00+00:00"Gallegos, A. D."https://www.zbmath.org/authors/?q=ai:gallegos.a-d"Gürsoy, U."https://www.zbmath.org/authors/?q=ai:gursoy.umutSummary: We explore the role of torsion as source of spin current in strongly interacting conformal fluids using holography. We establish the constitutive relations of the basic hydrodynamic variables, the energy-momentum tensor and the spin current based on the classification of the spin sources in irreducible Lorentz representations. The fluids we consider are assumed to be described by the five dimensional Lovelock-Chern-Simons gravity with independent vielbein and spin connection. We construct a hydrodynamic expansion that involves the stress tensor and the spin current and compute the corresponding one-point functions holographically. As a byproduct we find a class of interesting analytic solutions to the Lovelock-Chern-Simons gravity, including blackholes, by mapping the equations of motion into non-linear algebraic constraints for the sources. We also derive a Lee-Wald entropy formula for these black holes in Chern-Simons theories with torsion. The black hole solutions determine the thermodynamic potentials and the hydrodynamic constitutive relations in the corresponding fluid on the boundary. We observe novel spin induced transport in these holographic models: a dynamical version of the Barnett effect where vorticity generates a spin current and anomalous vortical transport transverse to a vector-like spin source.The large-\(N\) limit of the 4d \(\mathcal{N} = 1\) superconformal index.https://www.zbmath.org/1456.814212021-04-16T16:22:00+00:00"Cabo-Bizet, Alejandro"https://www.zbmath.org/authors/?q=ai:cabo-bizet.alejandro"Cassani, Davide"https://www.zbmath.org/authors/?q=ai:cassani.davide"Martelli, Dario"https://www.zbmath.org/authors/?q=ai:martelli.dario"Murthy, Sameer"https://www.zbmath.org/authors/?q=ai:murthy.sameerSummary: We systematically analyze the large-\(N\) limit of the superconformal index of \(\mathcal{N} = 1\) superconformal theories having a quiver description. The index of these theories is known in terms of unitary matrix integrals, which we calculate using the recently-developed technique of elliptic extension. This technique allows us to easily evaluate the integral as a sum over saddle points of an effective action in the limit where the rank of the gauge group is infinite. For a generic quiver theory under consideration, we find a special family of saddles whose effective action takes a universal form controlled by the anomaly coefficients of the theory. This family includes the known supersymmetric black hole solution in the holographically dual \( \mathrm{AdS}_5\) theories. We then analyze the index refined by turning on flavor chemical potentials. We show that, for a certain range of chemical potentials, the effective action again takes a universal cubic form that is controlled by the anomaly coefficients of the theory. Finally, we present a large class of solutions to the saddle-point equations which are labelled by group homomorphisms of finite abelian groups of order \(N\) into the torus.Effective theories as truncated trans-series and scale separated compactifications.https://www.zbmath.org/1456.813082021-04-16T16:22:00+00:00"Emelin, Maxim"https://www.zbmath.org/authors/?q=ai:emelin.maximSummary: We study the possibility of realizing scale-separated type IIB Anti-de Sitter and de Sitter compactifications within a controlled effective field theory regime defined by low-energy and large (but scale-separated) compactification volume. The approach we use views effective theories as truncations of the full quantum equations of motion expanded in a trans-series around this asymptotic regime. By studying the scalings of all possible perturbative and non-perturbative corrections we identify the effects that have the right scaling to allow for the desired solutions. In the case of Anti-de Sitter, we find agreement with KKLT-type scenarios, and argue that non-perturbative brane-instantons wrapping four-cycles (or similarly scaling effects) are essentially the only ingredient that allows for scale separated solutions. We also comment on the relation of these results to the AdS swampland conjectures. For the de Sitter case we find that we are forced to introduce an infinite number of relatively unsuppressed corrections to the equations of motion, leading to a breakdown of effective theory. This suggests that if de Sitter vacua exist in the string landscape, they should not be thought of as residing within the same effective theory as the AdS or Minkowski compactifications, but rather as defining a separate asymptotic regime, presumably related to the others by a duality transformation.The Poincaré and BMS flux-balance laws with application to binary systems.https://www.zbmath.org/1456.830152021-04-16T16:22:00+00:00"Compère, Geoffrey"https://www.zbmath.org/authors/?q=ai:compere.geoffrey"Oliveri, Roberto"https://www.zbmath.org/authors/?q=ai:oliveri.roberto"Seraj, Ali"https://www.zbmath.org/authors/?q=ai:seraj.aliSummary: Asymptotically flat spacetimes admit both supertranslations and Lorentz transformations as asymptotic symmetries. Furthermore, they admit super-Lorentz transformations, namely superrotations and superboosts, as outer symmetries associated with super-angular momentum and super-center-of-mass charges. In this paper, we present comprehensively the flux-balance laws for all such BMS charges. We distinguish the Poincaré flux-balance laws from the proper BMS flux-balance laws associated with the three relevant memory effects defined from the shear, namely, the displacement, spin and center-of-mass memory effects. We scrutinize the prescriptions used to define the angular momentum and center-of-mass. In addition, we provide the exact form of all Poincaré and proper BMS flux-balance laws in terms of radiative symmetric tracefree multipoles. Fluxes of energy, angular momentum and octupole super-angular momentum arise at 2.5PN, fluxes of quadrupole supermomentum arise at 3PN and fluxes of momentum, center-of-mass and octupole super-center-of-mass arise at 3.5PN. We also show that the BMS flux-balance laws lead to integro-differential consistency constraints on the radiation-reaction forces acting on the sources. Finally, we derive the exact form of all BMS charges for both an initial Kerr binary and a final Kerr black hole in an arbitrary Lorentz and supertranslation frame, which allows to derive exact constraints on gravitational waveforms produced by binary black hole mergers from each BMS flux-balance law.A scattering amplitude in conformal field theory.https://www.zbmath.org/1456.813782021-04-16T16:22:00+00:00"Gillioz, Marc"https://www.zbmath.org/authors/?q=ai:gillioz.marc"Meineri, Marco"https://www.zbmath.org/authors/?q=ai:meineri.marco"Penedones, João"https://www.zbmath.org/authors/?q=ai:penedones.joaoSummary: We define form factors and scattering amplitudes in conformal field theory as the coefficient of the singularity of the Fourier transform of time-ordered correlation functions, as \(p^2 \rightarrow 0\). In particular, we study a form factor \(F(s, t, u) \) obtained from a four-point function of identical scalar primary operators. We show that \(F\) is crossing symmetric, analytic and it has a partial wave expansion. We illustrate our findings in the \textit{3d} Ising model, perturbative fixed points and holographic CFTs.De Sitter in non-supersymmetric string theories: no-go theorems and brane-worlds.https://www.zbmath.org/1456.830882021-04-16T16:22:00+00:00"Basile, Ivano"https://www.zbmath.org/authors/?q=ai:basile.ivano"Lanza, Stefano"https://www.zbmath.org/authors/?q=ai:lanza.stefanoSummary: We study de Sitter configurations in ten-dimensional string models where supersymmetry is either absent or broken at the string scale. To this end, we derive expressions for the cosmological constant in general warped flux compactifications with localized sources, which yield no-go theorems that extend previous works on supersymmetric cases. We frame our results within a dimensional reduction and connect them to a number of Swampland conjectures, corroborating them further in the absence of supersymmetry. Furthermore, we construct a top-down string embedding of de Sitter brane-world cosmologies within unstable anti-de Sitter landscapes, providing a concrete realization of a recently revisited proposal.Quantum BTZ black hole.https://www.zbmath.org/1456.830232021-04-16T16:22:00+00:00"Emparan, Roberto"https://www.zbmath.org/authors/?q=ai:emparan.roberto"Frassino, Antonia Micol"https://www.zbmath.org/authors/?q=ai:frassino.antonia-micol"Way, Benson"https://www.zbmath.org/authors/?q=ai:way.bensonSummary: We study a holographic construction of quantum rotating BTZ black holes that incorporates the exact backreaction from strongly coupled quantum conformal fields. It is based on an exact four-dimensional solution for a black hole localized on a brane in \( \mathrm{AdS}_4\), first discussed some years ago but never fully investigated in this manner. Besides quantum CFT effects and their backreaction, we also investigate the role of higher-curvature corrections in the effective three-dimensional theory. We obtain the quantum-corrected geometry and the renormalized stress tensor. We show that the quantum black hole entropy, which includes the entanglement of the fields outside the horizon, satisfies the first law of thermodynamics exactly, even in the presence of backreaction and with higher-curvature corrections, while the Bekenstein-Hawking-Wald entropy does not. This result, which involves a rather non-trivial bulk calculation, shows the consistency of the holographic interpretation of braneworlds. We compare our renormalized stress tensor to results derived for free conformal fields, and for a previous holographic construction without backreaction effects, which is shown to be a limit of the solutions in this article.Graviton-mediated scattering amplitudes from the quantum effective action.https://www.zbmath.org/1456.830222021-04-16T16:22:00+00:00"Draper, Tom"https://www.zbmath.org/authors/?q=ai:draper.tom"Knorr, Benjamin"https://www.zbmath.org/authors/?q=ai:knorr.benjamin"Ripken, Chris"https://www.zbmath.org/authors/?q=ai:ripken.chris"Saueressig, Frank"https://www.zbmath.org/authors/?q=ai:saueressig.frankSummary: We employ the curvature expansion of the quantum effective action for gravity-matter systems to construct graviton-mediated scattering amplitudes for non-minimally coupled scalar fields in a Minkowski background. By design, the formalism parameterises all quantum corrections to these processes and is manifestly gauge-invariant. The conditions resulting from UV-finiteness, unitarity, and causality are analysed in detail and it is shown by explicit construction that the quantum effective action provides sufficient room to meet these structural requirements without introducing non-localities or higher-spin degrees of freedom. Our framework provides a bottom-up approach to all quantum gravity programs seeking for the quantisation of gravity within the framework of quantum field theory. Its scope is illustrated by specific examples, including effective field theory, Stelle gravity, infinite derivative gravity, and Asymptotic Safety.Remarks on black hole complexity puzzle.https://www.zbmath.org/1456.830482021-04-16T16:22:00+00:00"Yoshida, Beni"https://www.zbmath.org/authors/?q=ai:yoshida.beniSummary: Recently a certain conceptual puzzle in the AdS/CFT correspondence, concerning the growth of quantum circuit complexity and the wormhole volume, has been identified by Bouland-Fefferman-Vazirani and Susskind. In this note, we propose a resolution of the puzzle and save the quantum Extended Church-Turing thesis by arguing that there is no computational shortcut in measuring the volume due to gravitational backreaction from bulk observers. A certain strengthening of the firewall puzzle from the computational complexity perspective, as well as its potential resolution, is also presented.Two interacting scalars system in curved spacetime --- vacuum stability from the curved spacetime effective field theory (cEFT) perspective.https://www.zbmath.org/1456.830352021-04-16T16:22:00+00:00"Lalak, Zygmunt"https://www.zbmath.org/authors/?q=ai:lalak.zygmunt"Nakonieczna, Anna"https://www.zbmath.org/authors/?q=ai:nakonieczna.anna"Nakonieczny, Łukasz"https://www.zbmath.org/authors/?q=ai:nakonieczny.lukaszSummary: In this article we investigated the influence of the gravity mediated higher dimensional operators on the issue of vacuum stability in a model containing two interacting scalar fields. As a framework we used the curved spacetime Effective Field Theory (cEFT) applied to the aforementioned system in which one of the scalars is heavy. After integrating out the heavy scalar we used the standard Euclidean approach to the obtained cEFT. Apart from analyzing the influence of standard operators like the non-minimal coupling to gravity and the dimension six contribution to the scalar field potential, we also investigated the rarely discussed dimension six contribution to the kinetic term and the new gravity mediated contribution to the scalar quartic self-interaction.Dressed minimal surfaces in \( \mathrm{AdS}_4\).https://www.zbmath.org/1456.831042021-04-16T16:22:00+00:00"Katsinis, Dimitrios"https://www.zbmath.org/authors/?q=ai:katsinis.dimitrios"Manolopoulos, Dimitrios"https://www.zbmath.org/authors/?q=ai:manolopoulos.dimitrios"Mitsoulas, Ioannis"https://www.zbmath.org/authors/?q=ai:mitsoulas.ioannis"Pastras, Georgios"https://www.zbmath.org/authors/?q=ai:pastras.georgiosSummary: We apply an arbitrary number of dressing transformations to a static minimal surface in \( \mathrm{AdS}_4\). Interestingly, a single dressing transformation, with the simplest dressing factor, interrelates the latter to solutions of the Euclidean non linear sigma model in \( \mathrm{dS}_3\). We present an expression for the area element of the dressed minimal surface in terms of that of the initial one and comment on the boundary region of the dressed surface. Finally, we apply the above formalism to the elliptic minimal surfaces and obtain new ones.String defects, supersymmetry and the Swampland.https://www.zbmath.org/1456.830862021-04-16T16:22:00+00:00"Angelantonj, Carlo"https://www.zbmath.org/authors/?q=ai:angelantonj.carlo"Bonnefoy, Quentin"https://www.zbmath.org/authors/?q=ai:bonnefoy.quentin"Condeescu, Cezar"https://www.zbmath.org/authors/?q=ai:condeescu.cezar"Dudas, Emilian"https://www.zbmath.org/authors/?q=ai:dudas.emilianSummary: Recently, Kim, Shiu and Vafa proposed general consistency conditions for six dimensional supergravity theories with minimal supersymmetry coming from couplings to strings. We test them in explicit perturbative orientifold models in order to unravel the microscopic origin of these constraints. Based on the perturbative data, we conjecture the existence of null charges \(Q \bullet Q = 0\) for any six-dimensional theory with at least one tensor multiplet, coupling to string defects of charge \(Q\). We then include the new constraint to exclude some six-dimensional supersymmetric anomaly-free examples that have currently no string or F-theory realization. We also investigate the constraints from the couplings to string defects in case where supersymmetry is broken in tachyon free vacua, containing non-BPS configurations of brane supersymmetry breaking type, where the breaking is localized on antibranes. In this case, some conditions have naturally to be changed or relaxed whenever the string defects experience supersymmetry breaking, whereas the constraints are still valid if they are geometrically separated from the supersymmetry breaking source.Classical algebraic structures in string theory effective actions.https://www.zbmath.org/1456.830982021-04-16T16:22:00+00:00"Erbin, Harold"https://www.zbmath.org/authors/?q=ai:erbin.harold"Maccaferri, Carlo"https://www.zbmath.org/authors/?q=ai:maccaferri.carlo"Schnabl, Martin"https://www.zbmath.org/authors/?q=ai:schnabl.martin"Vošmera, Jakub"https://www.zbmath.org/authors/?q=ai:vosmera.jakubSummary: We study generic properties of string theory effective actions obtained by classically integrating out massive excitations from string field theories based on cyclic homotopy algebras of \(A_\infty\) or \(L_\infty\) type. We construct observables in the UV theory and we discuss their fate after integration-out. Furthermore, we discuss how to compose two subsequent integrations of degrees of freedom (horizontal composition) and how to integrate out degrees of freedom after deforming the UV theory with a new consistent interaction (vertical decomposition). We then apply our general results to the open bosonic string using Witten's open string field theory. There we show how the horizontal composition can be used to systematically integrate out the Nakanishi-Lautrup field from the set of massless excitations, ending with a non-abelian \(A_\infty \)-gauge theory for just the open string gluon. Moreover we show how the vertical decomposition can be used to construct effective open-closed couplings by deforming Witten OSFT with a tadpole given by the Ellwood invariant. Also, we discuss how the effective theory controls the possibility of removing the tadpole in the microscopic theory, giving a new framework for studying D-brane deformations induced by changes in the closed string background.More on Wilson toroidal networks and torus blocks.https://www.zbmath.org/1456.830542021-04-16T16:22:00+00:00"Alkalaev, Konstantin"https://www.zbmath.org/authors/?q=ai:alkalaev.konstantin"Belavin, Vladimir"https://www.zbmath.org/authors/?q=ai:belavin.vladimir-aSummary: We consider the Wilson line networks of the Chern-Simons \(3d\) gravity theory with toroidal boundary conditions which calculate global conformal blocks of degenerate quasi-primary operators in torus \(2d\) CFT. After general discussion that summarizes and further extends results known in the literature we explicitly obtain the one-point torus block and two-point torus blocks through particular matrix elements of toroidal Wilson network operators in irreducible finite-dimensional representations of \(sl (2, \mathbb{R})\) algebra. The resulting expressions are given in two alternative forms using different ways to treat multiple tensor products of \(sl (2, \mathbb{R})\) representations: (1) 3\textit{mj} Wigner symbols and intertwiners of higher valence, (2) totally symmetric tensor products of the fundamental \(sl (2, \mathbb{R})\) representation.Asymptotic symmetries of Yang-Mills fields in Hamiltonian formulation.https://www.zbmath.org/1456.830162021-04-16T16:22:00+00:00"Tanzi, Roberto"https://www.zbmath.org/authors/?q=ai:tanzi.roberto"Giulini, Domenico"https://www.zbmath.org/authors/?q=ai:giulini.domenico-j-wSummary: We investigate the asymptotic symmetry group of the free \(\mathrm{SU} (N)\)-Yang-Mills theory using the Hamiltonian formalism. We closely follow the strategy of Henneaux and Troessaert who successfully applied the Hamiltonian formalism to the case of gravity and electrodynamics, thereby deriving the respective asymptotic symmetry groups of these theories from clear-cut first principles. These principles include the minimal assumptions that are necessary to ensure the existence of Hamiltonian structures (phase space, symplectic form, differentiable Hamiltonian) and, in case of Poincaré invariant theories, a canonical action of the Poincaré group. In the first part of the paper we show how these requirements can be met in the non-abelian \(\mathrm{SU} (N)\)-Yang-Mills case by imposing suitable fall-off and parity conditions on the fields. We observe that these conditions admit neither non-trivial asymptotic symmetries nor non-zero global charges. In the second part of the paper we discuss possible gradual relaxations of these conditions by following the same strategy that Henneaux and Troessaert had employed to remedy a similar situation in the electromagnetic case. Contrary to our expectation and the findings of Henneaux and Troessaert for the abelian case, there seems to be no relaxation that meets the requirements of a Hamiltonian formalism \textit{and} allows for non-trivial asymptotic symmetries and charges. Non-trivial asymptotic symmetries and charges are only possible if either the Poincaré group fails to act canonically or if the formal expression for the symplectic form diverges, i.e. the form does not exist. This seems to hint at a kind of colour-confinement built into the classical Hamiltonian formulation of non-abelian gauge theories.Relativistic gas in a Schwarzschild metric.https://www.zbmath.org/1456.761622021-04-16T16:22:00+00:00"Kremer, Gilberto M."https://www.zbmath.org/authors/?q=ai:kremer.gilberto-medeirosTowards spacetime entanglement entropy for interacting theories.https://www.zbmath.org/1456.830172021-04-16T16:22:00+00:00"Chen, Yangang"https://www.zbmath.org/authors/?q=ai:chen.yangang"Hackl, Lucas"https://www.zbmath.org/authors/?q=ai:hackl.lucas"Kunjwal, Ravi"https://www.zbmath.org/authors/?q=ai:kunjwal.ravi"Moradi, Heidar"https://www.zbmath.org/authors/?q=ai:moradi.heidar"Yazdi, Yasaman K."https://www.zbmath.org/authors/?q=ai:yazdi.yasaman-k"Zilhão, Miguel"https://www.zbmath.org/authors/?q=ai:zilhao.miguelSummary: Entanglement entropy of quantum fields in gravitational settings is a topic of growing importance. This entropy of entanglement is conventionally computed relative to Cauchy hypersurfaces where it is possible via a partial tracing to associate a reduced density matrix to the spacelike region of interest. In recent years Sorkin has proposed an alternative, manifestly covariant, formulation of entropy in terms of the spacetime two-point correlation function. This formulation, developed for a Gaussian scalar field theory, is explicitly spacetime in nature and evades some of the possible non-covariance issues faced by the conventional formulation. In this paper we take the first steps towards extending Sorkin's entropy to non-Gaussian theories where Wick's theorem no longer holds and one would expect higher correlators to contribute. We consider quartic perturbations away from the Gaussian case and find that to first order in perturbation theory, the entropy formula derived by Sorkin continues to hold but with the two-point correlators replaced by their perturbation-corrected counterparts. We then show that our results continue to hold for arbitrary perturbations (of both bosonic and fermionic theories). This is a non-trivial and, to our knowledge, novel result. Furthermore we also derive closed-form formulas of the entanglement entropy for arbitrary perturbations at first and second order. Our work also suggests avenues for further extensions to generic interacting theories.Systematics of type IIA moduli stabilisation.https://www.zbmath.org/1456.831052021-04-16T16:22:00+00:00"Marchesano, Fernando"https://www.zbmath.org/authors/?q=ai:marchesano.fernando"Prieto, David"https://www.zbmath.org/authors/?q=ai:prieto.david"Quirant, Joan"https://www.zbmath.org/authors/?q=ai:quirant.joan"Shukla, Pramod"https://www.zbmath.org/authors/?q=ai:shukla.pramod-sSummary: We analyse the flux-induced scalar potential for type IIA orientifolds in the presence of \(p\)-form, geometric and non-geometric fluxes. Just like in the Calabi-Yau case, the potential presents a bilinear structure, with a factorised dependence on axions and saxions. This feature allows one to perform a systematic search for vacua, which we implement for the case of geometric backgrounds. Guided by stability criteria, we consider configurations with a particular on-shell F-term pattern, and show that no de Sitter extrema are allowed for them. We classify branches of supersymmetric and non-supersymmetric vacua, and argue that the latter are perturbatively stable for a large subset of them. Our solutions reproduce and generalise previous results in the literature, obtained either from the 4d or 10d viewpoint.Random boundary geometry and gravity dual of \(T\overline{T}\) deformation.https://www.zbmath.org/1456.813842021-04-16T16:22:00+00:00"Hirano, Shinji"https://www.zbmath.org/authors/?q=ai:hirano.shinji"Shigemori, Masaki"https://www.zbmath.org/authors/?q=ai:shigemori.masakiSummary: We study the random geometry approach to the \(T\overline{T}\) deformation of \(2d\) conformal field theory developed by Cardy and discuss its realization in a gravity dual. In this representation, the gravity dual of the \(T\overline{T}\) deformation becomes a straightforward translation of the field theory language. Namely, the dual geometry is an ensemble of \( \mathrm{AdS}_3\) spaces or BTZ black holes, without a finite cutoff, but instead with randomly fluctuating boundary diffeomorphisms. This reflects an increase in degrees of freedom in the renormalization group flow to the UV by the irrelevant \(T\overline{T}\) operator. We streamline the method of computation and calculate the energy spectrum and the thermal free energy in a manner that can be directly translated into the gravity dual language. We further generalize this approach to correlation functions and reproduce the all-order result with universal logarithmic corrections computed by Cardy in a different method. In contrast to earlier proposals, this version of the gravity dual of the \(T\overline{T}\) deformation works not only for the energy spectrum and the thermal free energy but also for correlation functions.4-point function from conformally coupled scalar in \( \mathrm{AdS}_6\).https://www.zbmath.org/1456.813952021-04-16T16:22:00+00:00"Oh, Jae-Hyuk"https://www.zbmath.org/authors/?q=ai:oh.jae-hyukSummary: We explore conformally coupled scalar theory in \( \mathrm{AdS}_6\) extensively and their classical solutions by employing power expansion order by order in its self-interaction coupling \(\lambda \). We describe how we get the classical solutions by diagrammatic ways which show general rules constructing the classical solutions. We study holographic correlation functions of scalar operator deformations to a certain 5-dimensional conformal field theory where the operators share the same scaling dimension \(\Delta = 3\), from the classical solutions. We do not assume any specific form of the micro Lagrangian density of the 5-dimensional conformal field theory. For our solutions, we choose a scheme where we remove co-linear divergences of momenta along the AdS boundary directions which frequently appear in the classical solutions. This shows clearly that the holographic correlation functions are free from the co-linear divergences. It turns out that this theory provides correct conformal 2- and 3- point functions of the \(\Delta = 3\) scalar operators as expected in previous literature. It makes sense since 2- and 3- point functions are determined by global conformal symmetry not being dependent on the details of the conformal theory. We also get 4-point function from this holographic model. In fact, it turns out that the 4-point correlation function is not conformal because it does not satisfy the special conformal Ward identity although it does dilation Ward identity and respect \(\operatorname{SO}(5)\) rotation symmetry. However, in the co-linear limit that all the external momenta are in a same direction, the 4-point function is conformal which means that it satisfy the special conformal Ward identity. We inspect holographic \(n\)-point functions of this theory which can be obtained by employing a certain Feynman-like rule. This rule is a construction of \(n\)-point function by connecting \(l\)-point functions each other where \( l < n \). In the co-linear limit, these \(n\)-point functions reproduce the conformal \(n\)-point functions of \(\Delta = 3\) scalar operators in \(d = 5\) Euclidean space addressed in [the author, ``A conformal scalar \(n\)-point function in momentum space'', Preprint, \url{arXiv:2001.05379}].Breaking supersymmetry with pure spinors.https://www.zbmath.org/1456.830492021-04-16T16:22:00+00:00"Legramandi, Andrea"https://www.zbmath.org/authors/?q=ai:legramandi.andrea"Tomasiello, Alessandro"https://www.zbmath.org/authors/?q=ai:tomasiello.alessandroSummary: For several classes of BPS vacua, we find a procedure to modify the PDEs that imply preserved supersymmetry and the equations of motion so that they still imply the latter but not the former. In each case we trace back this supersymmetry-breaking deformation to a distinct modification of the pure spinor equations that provide a geometrical interpretation of supersymmetry. We give some concrete examples: first we generalize the Imamura class of \(Mink_6\) solutions by removing a symmetry requirement, and then derive some local and global solutions both before and after breaking supersymmetry.Shocks, superconvergence, and a stringy equivalence principle.https://www.zbmath.org/1456.830282021-04-16T16:22:00+00:00"Koloğlu, Murat"https://www.zbmath.org/authors/?q=ai:kologlu.murat"Kravchuk, Petr"https://www.zbmath.org/authors/?q=ai:kravchuk.petr"Simmons-Duffin, David"https://www.zbmath.org/authors/?q=ai:simmons-duffin.david"Zhiboedov, Alexander"https://www.zbmath.org/authors/?q=ai:zhiboedov.alexanderSummary: We study propagation of a probe particle through a series of closely situated gravitational shocks. We argue that in any UV-complete theory of gravity the result does not depend on the shock ordering --- in other words, coincident gravitational shocks commute. Shock commutativity leads to nontrivial constraints on low-energy effective theories. In particular, it excludes non-minimal gravitational couplings unless extra degrees of freedom are judiciously added. In flat space, these constraints are encoded in the vanishing of a certain ``superconvergence sum rule.'' In AdS, shock commutativity becomes the statement that average null energy (ANEC) operators commute in the dual CFT. We prove commutativity of ANEC operators in any unitary CFT and establish sufficient conditions for commutativity of more general light-ray operators. Superconvergence sum rules on CFT data can be obtained by inserting complete sets of states between light-ray operators. In a planar 4d CFT, these sum rules express \(\frac{a-c}{c}\) in terms of the OPE data of single-trace operators.Gauges in three-dimensional gravity and holographic fluids.https://www.zbmath.org/1456.830552021-04-16T16:22:00+00:00"Ciambelli, Luca"https://www.zbmath.org/authors/?q=ai:ciambelli.luca"Marteau, Charles"https://www.zbmath.org/authors/?q=ai:marteau.charles"Petropoulos, P. Marios"https://www.zbmath.org/authors/?q=ai:petropoulos.p-marios"Ruzziconi, Romain"https://www.zbmath.org/authors/?q=ai:ruzziconi.romainSummary: Solutions to Einstein's vacuum equations in three dimensions are locally maximally symmetric. They are distinguished by their global properties and their investigation often requires a choice of gauge. Although analyses of this sort have been performed abundantly, several relevant questions remain. These questions include the interplay between the standard Bondi gauge and the Eddington-Finkelstein type of gauge used in the fluid/gravity holographic reconstruction of these spacetimes, as well as the Fefferman-Graham gauge, when available i.e. in anti de Sitter. The goal of the present work is to set up a thorough dictionary for the available descriptions with emphasis on the relativistic or Carrollian holographic fluids, which portray the bulk from the boundary in anti-de Sitter or flat instances. A complete presentation of residual diffeomorphisms with a preliminary study of their algebra accompanies the situations addressed here.Integrable systems and the boundary dynamics of higher spin gravity on \( \mathrm{AdS}_3\).https://www.zbmath.org/1456.830682021-04-16T16:22:00+00:00"Ojeda, Emilio"https://www.zbmath.org/authors/?q=ai:ojeda.emilio"Pérez, Alfredo"https://www.zbmath.org/authors/?q=ai:perez.alfredoSummary: We introduce a new set of boundary conditions for three-dimensional higher spin gravity with gauge group \( \mathrm{SL} (3, \mathbb{R}) \times \mathrm{SL} (3, \mathbb{R})\), where its dynamics at the boundary is described by the members of the modified Boussinesq integrable hierarchy. In the asymptotic region the gauge fields are written in the diagonal gauge, where the excitations go along the generators of the Cartan subalgebra of \(sl (3, \mathbb{R}) \oplus sl (3, \mathbb{R})\). We show that the entire integrable structure of the modified Boussinesq hierarchy, i.e., the phase space, the Poisson brackets and the infinite number of commuting conserved charges, are obtained from the asymptotic structure of the higher spin theory. Furthermore, its known relation with the Boussinesq hierarchy is inherited from our analysis once the asymptotic conditions are re-expressed in the highest weight gauge. Hence, the Miura map is recovered from a purely geometric construction in the bulk. Black holes that fit within our boundary conditions, the Hamiltonian reduction at the boundary, and the generalization to higher spin gravity with gauge group \( \mathrm{SL} (N, \mathbb{R}) \times \mathrm{SL} (N, \mathbb{R})\) are also discussed.Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points.https://www.zbmath.org/1456.830812021-04-16T16:22:00+00:00"Inkof, Gian Andrea"https://www.zbmath.org/authors/?q=ai:inkof.gian-andrea"Küppers, Joachim M. C."https://www.zbmath.org/authors/?q=ai:kuppers.joachim-m-c"Link, Julia M."https://www.zbmath.org/authors/?q=ai:link.julia-m"Goutéraux, Blaise"https://www.zbmath.org/authors/?q=ai:gouteraux.blaise"Schmalian, Jörg"https://www.zbmath.org/authors/?q=ai:schmalian.jorgSummary: The transport behavior of strongly anisotropic systems is significantly richer compared to isotropic ones. The most dramatic spatial anisotropy at a critical point occurs at a Lifshitz transition, found in systems with merging Dirac or Weyl point or near the superconductor-insulator quantum phase transition. Previous work found that in these systems a famous conjecture on the existence of a lower bound for the ratio of a shear viscosity to entropy is violated, and proposed a generalization of this bound for anisotropic systems near charge neutrality involving the electric conductivities. The present study uses scaling arguments and the gauge-gravity duality to confirm the previous analysis of universal bounds in anisotropic Dirac systems. We investigate the strongly-coupled phase of quantum Lifshitz systems in a gravitational Einstein-Maxwell-dilaton model with a linear massless scalar which breaks translations in the boundary dual field theory and sources the anisotropy. The holographic computation demonstrates that some elements of the viscosity tensor can be related to the ratio of the electric conductivities through a simple geometric ratio of elements of the bulk metric evaluated at the horizon, and thus obey a generalized bound, while others violate it. From the IR critical geometry, we express the charge diffusion constants in terms of the square butterfly velocities. The proportionality factor turns out to be direction-independent, linear in the inverse temperature, and related to the critical exponents which parametrize the anisotropic scaling of the dual field theory.\( T\overline{T} \)-deformation of \(q\)-Yang-Mills theory.https://www.zbmath.org/1456.830692021-04-16T16:22:00+00:00"Santilli, Leonardo"https://www.zbmath.org/authors/?q=ai:santilli.leonardo"Szabo, Richard J."https://www.zbmath.org/authors/?q=ai:szabo.richard-j"Tierz, Miguel"https://www.zbmath.org/authors/?q=ai:tierz.miguelSummary: We derive the \(T\overline{T} \)-perturbed version of two-dimensional \(q\)-deformed Yang-Mills theory on an arbitrary Riemann surface by coupling the unperturbed theory in the first order formalism to Jackiw-Teitelboim gravity. We show that the \(T\overline{T} \)-deformation results in a breakdown of the connection with a Chern-Simons theory on a Seifert manifold, and of the large \(N\) factorization into chiral and anti-chiral sectors. For the \( \mathrm{U} (N)\) gauge theory on the sphere, we show that the large \(N\) phase transition persists, and that it is of third order and induced by instantons. The effect of the \(T\overline{T} \)-deformation is to decrease the critical value of the 't Hooft coupling, and also to extend the class of line bundles for which the phase transition occurs. The same results are shown to hold for \( (q,t) \)-deformed Yang-Mills theory. We also explicitly evaluate the entanglement entropy in the large \(N\) limit of Yang-Mills theory, showing that the \(T\overline{T} \)-deformation decreases the contribution of the Boltzmann entropy.Relaxing unimodularity for Yang-Baxter deformed strings.https://www.zbmath.org/1456.831032021-04-16T16:22:00+00:00"Hronek, Stanislav"https://www.zbmath.org/authors/?q=ai:hronek.stanislav"Wulff, Linus"https://www.zbmath.org/authors/?q=ai:wulff.linusSummary: We consider so-called Yang-Baxter deformations of bosonic string sigma- models, based on an \(R\)-matrix solving the (modified) classical Yang-Baxter equation. It is known that a unimodularity condition on \(R\) is sufficient for Weyl invariance at least to two loops (first order in \(\alpha^\prime)\). Here we ask what the necessary condition is. We find that in cases where the matrix \((G + B)_{ mn }\), constructed from the metric and \(B\)-field of the undeformed background, is degenerate the unimodularity condition arising at one loop can be replaced by weaker conditions. We further show that for non-unimodular deformations satisfying the one-loop conditions the Weyl invariance extends at least to two loops (first order in \(\alpha^\prime)\). The calculations are simplified by working in an \(O(D,D)\)-covariant doubled formulation.Global aspects of spaces of vacua.https://www.zbmath.org/1456.831082021-04-16T16:22:00+00:00"Sharon, Adar"https://www.zbmath.org/authors/?q=ai:sharon.adarSummary: We study ``vacuum crossing'', which occurs when the vacua of a theory are exchanged as we vary some periodic parameter \(\theta\) in a closed loop. We show that vacuum crossing is a useful non-perturbative tool to study strongly-coupled quantum field theories, since finding vacuum crossing in a weakly-coupled regime of the theory can lead to nontrivial consequences in the strongly-coupled regime. We start by discussing a mechanism where vacuum crossing occurs due to an anomaly, and then discuss some applications of vacuum crossing in general. In particular, we argue that vacuum crossing can be used to check IR dualities and to look for emergent IR symmetries.Towards an explicit construction of de Sitter solutions in classical supergravity.https://www.zbmath.org/1456.830092021-04-16T16:22:00+00:00"Kim, Nakwoo"https://www.zbmath.org/authors/?q=ai:kim.nakwooSummary: We revisit the stringy construction of four-dimensional de-Sitter solutions using orientifolds \(O8_\pm\), proposed by \textit{C. Córdova} et al. [``Classical de Sitter solutions of 10-dimensional supergravity'', Phys. rev. Lett. 122, No. 9, Article ID 091601, 5 p. (2019; \url{doi:10.1103/PhysRevLett.122.091601})]. While the original analysis of the supergravity equations is largely numerical, we obtain semi-analytic solutions by treating the curvature as a perturbative parameter. At each order we verify that the (permissive) boundary conditions at the orientifolds are satisfied. To illustrate the advantage of our result, we calculate the four-dimensional Newton constant as a function of the cosmological constant. We also discuss how the discontinuities at \(O8_-\) can be accounted for in terms of corrections to the worldvolume action.The unique Polyakov blocks.https://www.zbmath.org/1456.814032021-04-16T16:22:00+00:00"Sleight, Charlotte"https://www.zbmath.org/authors/?q=ai:sleight.charlotte"Taronna, Massimo"https://www.zbmath.org/authors/?q=ai:taronna.massimoSummary: In this work we present a closed form expression for Polyakov blocks in Mellin space for arbitrary spin and scaling dimensions. We provide a prescription to fix the contact term ambiguity uniquely by reducing the problem to that of fixing the contact term ambiguity at the level of cyclic exchange amplitudes --- defining cyclic Polyakov blocks --- in terms of which any fully crossing symmetric correlator can be decomposed. We also give another, equivalent, prescription which does not rely on a decomposition into cyclic amplitudes. We extract the OPE data of double-twist operators in the direct channel expansion of the cyclic Polyakov blocks using and extending the analysis of [\textit{C. Sleight} and \textit{M. Taronna}, J. High Energy Phys. 2018, No. 11, Paper No. 89, 62 p. (2018; Zbl 1404.81242)] to include contributions that are non-analytic in spin. The relation between cyclic Polyakov blocks and analytic Bootstrap functionals is underlined.CFT unitarity and the AdS Cutkosky rules.https://www.zbmath.org/1456.813902021-04-16T16:22:00+00:00"Meltzer, David"https://www.zbmath.org/authors/?q=ai:meltzer.david"Sivaramakrishnan, Allic"https://www.zbmath.org/authors/?q=ai:sivaramakrishnan.allicSummary: We derive the Cutkosky rules for conformal field theories (CFTs) at weak and strong coupling. These rules give a simple, diagrammatic method to compute the double-commutator that appears in the Lorentzian inversion formula. We first revisit weakly-coupled CFTs in flat space, where the cuts are performed on Feynman diagrams. We then generalize these rules to strongly-coupled holographic CFTs, where the cuts are performed on the Witten diagrams of the dual theory. In both cases, Cutkosky rules factorize loop diagrams into on-shell sub-diagrams and generalize the standard S-matrix cutting rules. These rules are naturally formulated and derived in Lorentzian momentum space, where the double-commutator is manifestly related to the CFT optical theorem. Finally, we study the AdS cutting rules in explicit examples at tree level and one loop. In these examples, we confirm that the rules are consistent with the OPE limit and that we recover the S-matrix optical theorem in the flat space limit. The AdS cutting rules and the CFT dispersion formula together form a holographic unitarity method to reconstruct Witten diagrams from their cuts.Effective entropy of quantum fields coupled with gravity.https://www.zbmath.org/1456.830212021-04-16T16:22:00+00:00"Dong, Xi"https://www.zbmath.org/authors/?q=ai:dong.xi"Qi, Xiao-Liang"https://www.zbmath.org/authors/?q=ai:qi.xiao-liang"Shangnan, Zhou"https://www.zbmath.org/authors/?q=ai:shangnan.zhou"Yang, Zhenbin"https://www.zbmath.org/authors/?q=ai:yang.zhenbinSummary: Entanglement entropy, or von Neumann entropy, quantifies the amount of uncertainty of a quantum state. For quantum fields in curved space, entanglement entropy of the quantum field theory degrees of freedom is well-defined for a fixed background geometry. In this paper, we propose a generalization of the quantum field theory entanglement entropy by including dynamical gravity. The generalized quantity named effective entropy, and its Renyi entropy generalizations, are defined by analytic continuation of a replica calculation. The replicated theory is defined as a gravitational path integral with multiple copies of the original boundary conditions, with a co-dimension-2 brane at the boundary of region we are studying. We discuss different approaches to define the region in a gauge invariant way, and show that the effective entropy satisfies the quantum extremal surface formula. When the quantum fields carry a significant amount of entanglement, the quantum extremal surface can have a topology transition, after which an entanglement island region appears. Our result generalizes the Hubeny-Rangamani-Takayanagi formula of holographic entropy (with quantum corrections) to general geometries without asymptotic AdS boundary, and provides a more solid framework for addressing problems such as the Page curve of evaporating black holes in asymptotic flat spacetime. We apply the formula to two example systems, a closed two-dimensional universe and a four-dimensional maximally extended Schwarzchild black hole. We discuss the analog of the effective entropy in random tensor network models, which provides more concrete understanding of quantum information properties in general dynamical geometries. We show that, in absence of a large boundary like in AdS space case, it is essential to introduce ancilla that couples to the original system, in order for correctly characterizing quantum states and correlation functions in the random tensor network. Using the superdensity operator formalism, we study the system with ancilla and show how quantum information in the entanglement island can be reconstructed in a state-dependent and observer-dependent map. We study the closed universe (without spatial boundary) case and discuss how it is related to open universe.Heterotic backgrounds via generalised geometry: moment maps and moduli.https://www.zbmath.org/1456.830872021-04-16T16:22:00+00:00"Ashmore, Anthony"https://www.zbmath.org/authors/?q=ai:ashmore.anthony"Strickland-Constable, Charles"https://www.zbmath.org/authors/?q=ai:strickland-constable.charles"Tennyson, David"https://www.zbmath.org/authors/?q=ai:tennyson.david"Waldram, Daniel"https://www.zbmath.org/authors/?q=ai:waldram.danielSummary: We describe the geometry of generic heterotic backgrounds preserving minimal supersymmetry in four dimensions using the language of generalised geometry. They are characterised by an \( \mathrm{SU} (3) \times \mathrm{ Spin} (6 + n)\) structure within \( \mathrm{O}(6,6+ n) \times \mathbb{R}^+\) generalised geometry. Supersymmetry of the background is encoded in the existence of an involutive subbundle of the generalised tangent bundle and the vanishing of a moment map for the action of diffeomorphisms and gauge symmetries. We give both the superpotential and the Kähler potential for a generic background, showing that the latter defines a natural Hitchin functional for heterotic geometries. Intriguingly, this formulation suggests new connections to geometric invariant theory and an extended notion of stability. Finally we show that the analysis of infinitesimal deformations of these geometric structures naturally reproduces the known cohomologies that count the massless moduli of supersymmetric heterotic backgrounds.Exponential growth of out-of-time-order correlator without chaos: inverted harmonic oscillator.https://www.zbmath.org/1456.813252021-04-16T16:22:00+00:00"Hashimoto, Koji"https://www.zbmath.org/authors/?q=ai:hashimoto.koji"Huh, Kyoung-Bum"https://www.zbmath.org/authors/?q=ai:huh.kyoung-bum"Kim, Keun-Young"https://www.zbmath.org/authors/?q=ai:kim.keun-young"Watanabe, Ryota"https://www.zbmath.org/authors/?q=ai:watanabe.ryotaSummary: We provide a detailed examination of a thermal out-of-time-order correlator (OTOC) growing exponentially in time in systems without chaos. The system is a one-dimensional quantum mechanics with a potential whose part is an inverted harmonic oscillator. We numerically observe the exponential growth of the OTOC when the temperature is higher than a certain threshold. The Lyapunov exponent is found to be of the order of the classical Lyapunov exponent generated at the hilltop, and it remains non-vanishing even at high temperature. We adopt various shape of the potential and find these features universal. The study confirms that the exponential growth of the thermal OTOC does not necessarily mean chaos when the potential includes a local maximum. We also provide a bound for the Lyapunov exponent of the thermal OTOC in generic quantum mechanics in one dimension, which is of the same form as the chaos bound obtained by Maldacena, Shenker and Stanford.Ultra-stable charging of fast-scrambling SYK quantum batteries.https://www.zbmath.org/1456.812532021-04-16T16:22:00+00:00"Rosa, Dario"https://www.zbmath.org/authors/?q=ai:rosa.dario"Rossini, Davide"https://www.zbmath.org/authors/?q=ai:rossini.davide"Andolina, Gian Marcello"https://www.zbmath.org/authors/?q=ai:andolina.gian-marcello"Polini, Marco"https://www.zbmath.org/authors/?q=ai:polini.marco"Carrega, Matteo"https://www.zbmath.org/authors/?q=ai:carrega.matteoSummary: Collective behavior strongly influences the charging dynamics of quantum batteries (QBs). Here, we study the impact of nonlocal correlations on the energy stored in a system of \(N\) QBs. A unitary charging protocol based on a Sachdev-Ye-Kitaev (SYK) quench Hamiltonian is thus introduced and analyzed. SYK models describe strongly interacting systems with nonlocal correlations and fast thermalization properties. Here, we demonstrate that, once charged, the average energy stored in the QB is very stable, realizing an ultraprecise charging protocol. By studying fluctuations of the average energy stored, we show that temporal fluctuations are strongly suppressed by the presence of nonlocal correlations at all time scales. A comparison with other paradigmatic examples of many-body QBs shows that this is linked to the collective dynamics of the SYK model and its high level of entanglement. We argue that such feature relies on the fast scrambling property of the SYK Hamiltonian, and on its fast thermalization properties, promoting this as an ideal model for the ultimate temporal stability of a generic QB. Finally, we show that the temporal evolution of the ergotropy, a quantity that characterizes the amount of extractable work from a QB, can be a useful probe to infer the thermalization properties of a many-body quantum system.BMS modular diaries: torus one-point function.https://www.zbmath.org/1456.813502021-04-16T16:22:00+00:00"Bagchi, Arjun"https://www.zbmath.org/authors/?q=ai:bagchi.arjun"Nandi, Poulami"https://www.zbmath.org/authors/?q=ai:nandi.poulami"Saha, Amartya"https://www.zbmath.org/authors/?q=ai:saha.amartya"Zodinmawia"https://www.zbmath.org/authors/?q=ai:zodinmawia.Summary: Two dimensional field theories invariant under the Bondi-Metzner-Sachs (BMS) group are conjectured to be dual to asymptotically flat spacetimes in three dimensions. In this paper, we continue our investigations of the modular properties of these field theories. In particular, we focus on the BMS torus one-point function. We use two different methods to arrive at expressions for asymptotic structure constants for general states in the theory utilising modular properties of the torus one-point function. We then concentrate on the BMS highest weight representation, and derive a host of new results, the most important of which is the BMS torus block. In a particular limit of large weights, we derive the leading and sub-leading pieces of the BMS torus block, which we then use to rederive an expression for the asymptotic structure constants for BMS primaries. Finally, we perform a bulk computation of a probe scalar in the background of a flatspace cosmological solution based on the geodesic approximation to reproduce our field theoretic results.Giant Wilson loops and \( \mathrm{AdS}_2/ \mathrm{dCFT}_1\).https://www.zbmath.org/1456.814332021-04-16T16:22:00+00:00"Giombi, Simone"https://www.zbmath.org/authors/?q=ai:giombi.simone"Jiang, Jiaqi"https://www.zbmath.org/authors/?q=ai:jiang.jiaqi"Komatsu, Shota"https://www.zbmath.org/authors/?q=ai:komatsu.shotaSummary: The 1/2-BPS Wilson loop in \(\mathcal{N} = 4\) supersymmetric Yang-Mills theory is an important and well-studied example of conformal defect. In particular, much work has been done for the correlation functions of operator insertions on the Wilson loop in the fundamental representation. In this paper, we extend such analyses to Wilson loops in the large-rank symmetric and antisymmetric representations, which correspond to probe D3 and D5 branes with \( \mathrm{AdS}_2 \times S^2\) and \( \mathrm{AdS}_2 \times S^4\) worldvolume geometries, ending at the \( \mathrm{ AdS}_5\) boundary along a one-dimensional contour. We first compute the correlation functions of protected scalar insertions from supersymmetric localization, and obtain a representation in terms of multiple integrals that are similar to the eigenvalue integrals of the random matrix, but with important differences. Using ideas from the Fermi Gas formalism and the Clustering method, we evaluate their large \(N\) limit exactly as a function of the 't Hooft coupling. The results are given by simple integrals of polynomials that resemble the \(Q\)-functions of the Quantum Spectral Curve, with integration measures depending on the number of insertions. Next, we study the correlation functions of fluctuations on the probe D3 and D5 branes in AdS. We compute a selection of three- and four-point functions from perturbation theory on the D-branes, and show that they agree with the results of localization when restricted to supersymmetric kinematics. We also explain how the difference of the internal geometries of the D3 and D5 branes manifests itself in the localization computation.The UV fate of anomalous U(1)s and the Swampland.https://www.zbmath.org/1456.830952021-04-16T16:22:00+00:00"Craig, Nathaniel"https://www.zbmath.org/authors/?q=ai:craig.nathaniel"Garcia, Isabel Garcia"https://www.zbmath.org/authors/?q=ai:garcia-garcia.isabel"Kribs, Graham D."https://www.zbmath.org/authors/?q=ai:kribs.graham-dSummary: Massive U(1) gauge theories featuring parametrically light vectors are suspected to belong in the Swampland of consistent EFTs that cannot be embedded into a theory of quantum gravity. We study four-dimensional, chiral U(1) gauge theories that appear anomalous over a range of energies up to the scale of anomaly-cancelling massive chiral fermions. We show that such theories must be UV-completed at a finite cutoff below which a radial mode must appear, and cannot be decoupled --- a Stückelberg limit does not exist. When the infrared fermion spectrum contains a mixed U(1)-gravitational anomaly, this class of theories provides a toy model of a boundary into the Swampland, for sufficiently small values of the vector mass. In this context, we show that the limit of a parametrically light vector comes at the cost of a quantum gravity scale that lies parametrically below \(M_{ \mathrm{Pl}}\), and our result provides field theoretic evidence for the existence of a Swampland of EFTs that is disconnected from the subset of theories compatible with a gravitational UV-completion. Moreover, when the low energy theory also contains a \( \mathrm{U}(1)^3\) anomaly, the Weak Gravity Conjecture scale makes an appearance in the form of a quantum gravity cutoff for values of the gauge coupling above a certain critical size.Warped flatland.https://www.zbmath.org/1456.830582021-04-16T16:22:00+00:00"Detournay, Stéphane"https://www.zbmath.org/authors/?q=ai:detournay.stephane"Merbis, Wout"https://www.zbmath.org/authors/?q=ai:merbis.wout"Ng, Gim Seng"https://www.zbmath.org/authors/?q=ai:ng.gim-seng"Wutte, Raphaela"https://www.zbmath.org/authors/?q=ai:wutte.raphaelaSummary: We study warped flat geometries in three-dimensional topologically massive gravity. They are quotients of global warped flat spacetime, whose isometries are given by the 2-dimensional centrally extended Poincaré algebra. The latter can be obtained as a certain scaling limit of Warped \( \mathrm{AdS}_3\) space with a positive cosmological constant. We discuss the causal structure of the resulting spacetimes using projection diagrams. We study their charges and thermodynamics, together with asymptotic Killing vectors preserving a consistent set of boundary conditions including them. The asymptotic symmetry group is given by a Warped CFT algebra, with a vanishing current level. A generalization of the derivation of the Warped CFT Cardy formula applies in this case, reproducing the entropy of the warped flat cosmological spacetimes.Model-dependence of minimal-twist OPEs in \(d > 2\) holographic CFTs.https://www.zbmath.org/1456.830752021-04-16T16:22:00+00:00"Fitzpatrick, A. Liam"https://www.zbmath.org/authors/?q=ai:fitzpatrick.a-liam"Huang, Kuo-Wei"https://www.zbmath.org/authors/?q=ai:huang.kuo-wei"Meltzer, David"https://www.zbmath.org/authors/?q=ai:meltzer.david"Perlmutter, Eric"https://www.zbmath.org/authors/?q=ai:perlmutter.eric"Simmons-Duffin, David"https://www.zbmath.org/authors/?q=ai:simmons-duffin.davidSummary: Following recent work on heavy-light correlators in higher-dimensional conformal field theories (CFTs) with a large central charge \(C_T\), we clarify the properties of stress tensor composite primary operators of minimal twist, \([T^m]\), using arguments in both CFT and gravity. We provide an efficient proof that the three-point coupling \(\left\langle{\mathcal{O}}_L{\mathcal{O}}_L\left[{T}^m\right]\right\rangle \), where \({\mathcal{O}}_L\) is any light primary operator, is independent of the purely gravitational action. Next, we consider corrections to this coupling due to additional interactions in AdS effective field theory and the corresponding dual CFT. When the CFT contains a non-zero three-point coupling \(\left\langle TT{\mathcal{O}}_L\right\rangle \), the three-point coupling \(\left\langle{\mathcal{O}}_L{\mathcal{O}}_L\left[{T}^2\right]\right\rangle\) is modified at large \(C_T\) if \(\left\langle TT{\mathcal{O}}_L\right\rangle \sim \sqrt{C_T} \). This scaling is obeyed by the dilaton, by Kaluza-Klein modes of prototypical supergravity compactifications, and by scalars in stress tensor multiplets of supersymmetric CFTs. Quartic derivative interactions involving the graviton and the light probe field dual to \({\mathcal{O}}_L\) can also modify the minimal-twist couplings; these local interactions may be generated by integrating out a spin-\( \mathcal{l} \geq 2\) bulk field at tree level, or any spin \(\mathcal{l}\) at loop level. These results show how the minimal-twist OPE coefficients can depend on the higher-spin gap scale, even perturbatively.\( \mathrm{AdS}_3\) wormholes from a modular bootstrap.https://www.zbmath.org/1456.830572021-04-16T16:22:00+00:00"Cotler, Jordan"https://www.zbmath.org/authors/?q=ai:cotler.jordan-s"Jensen, Kristan"https://www.zbmath.org/authors/?q=ai:jensen.kristanSummary: In recent work we computed the path integral of three-dimensional gravity with negative cosmological constant on spaces which are topologically a torus times an interval. Here we employ a modular bootstrap to show that the amplitude is completely fixed by consistency conditions and a few basic inputs from gravity. This bootstrap is notably for an ensemble of CFTs, rather than for a single instance. We also compare the 3d gravity result with the Narain ensemble. The former is well-approximated at low temperature by a random matrix theory ansatz, and we conjecture that this behavior is generic for an ensemble of CFTs at large central charge with a chaotic spectrum of heavy operators.Strings in irrelevant deformations of \( \mathrm{AdS}_3/\mathrm{CFT}_2\).https://www.zbmath.org/1456.830912021-04-16T16:22:00+00:00"Chakraborty, Soumangsu"https://www.zbmath.org/authors/?q=ai:chakraborty.soumangsu"Giveon, Amit"https://www.zbmath.org/authors/?q=ai:giveon.amit"Kutasov, David"https://www.zbmath.org/authors/?q=ai:kutasov.davidSummary: We generalize our recent analysis [``\(T\bar{T}\), black holes and negative strings'', Preprint, \url{arXiv:2006.13249}] of probe string dynamics to the case of general single-trace \(T\overline{T}\), \(J\overline{T}\) and \(T\overline{J}\) deformations. We show that in regions in coupling space where the bulk geometry is smooth, the classical trajectories of such strings are smooth and approach the linear dilaton boundary at either the far past or the far future. These trajectories give rise to quantum scattering states with arbitrarily high energies. When the bulk geometry has closed timelike curves (CTC's), the trajectories are singular for energies above a critical value \(E_c \). This singularity occurs in the region with CTC's, and the value of \(E_c\) agrees with that read off from the dual boundary theory for all values of the couplings and charges.Holography and unitarity.https://www.zbmath.org/1456.830782021-04-16T16:22:00+00:00"Giddings, Steven B."https://www.zbmath.org/authors/?q=ai:giddings.steven-bSummary: If holography is an equivalence between quantum theories, one might expect it to be described by a map that is a bijective isometry between bulk and boundary Hilbert spaces, preserving the hamiltonian and symmetries. Holography has been believed to be a property of gravitational (or string) theories, but not of non-gravitational theories; specifically Marolf has argued that it originates from the gauge symmetries and constraints of gravity. These observations suggest study of the assumed holographic map as a function of the gravitational coupling \(G\). The zero coupling limit gives ordinary quantum field theory, and is therefore not necessarily expected to be holographic. This, and the structure of gravity at non-zero \(G\), raises important questions about the full map. In particular, construction of a holographic map appears to require as input a solution of the nonperturbative analog of the bulk gravitational constraints, that is, the unitary bulk evolution. Moreover, examination of the candidate boundary algebra, including the boundary hamiltonian, reveals commutators that don't close in the usual fashion expected for a boundary theory.Comments on the stability of the KPV state.https://www.zbmath.org/1456.830472021-04-16T16:22:00+00:00"Nguyen, Nam"https://www.zbmath.org/authors/?q=ai:nguyen.nam-anh|nguyen.nam-hoai|nguyen.nam-phuong|nguyen.nam-trung|nguyen.nam-ky|nguyen.nam-hai|nguyen.nam-tuanSummary: Using the blackfold approach, we study the classical stability of the KPV (Kachru-Pearson-Verlinde) state of anti-D3 branes at the tip of the Klebanov-Strassler throat. With regards to generic long-wavelength deformations considered, we found no instabilities. We comment on the relation of our results to existing results on the stability of the KPV state.Gravitational positivity bounds.https://www.zbmath.org/1456.830312021-04-16T16:22:00+00:00"Tokuda, Junsei"https://www.zbmath.org/authors/?q=ai:tokuda.junsei"Aoki, Katsuki"https://www.zbmath.org/authors/?q=ai:aoki.katsuki"Hirano, Shin'ichi"https://www.zbmath.org/authors/?q=ai:hirano.shinichiSummary: We study the validity of positivity bounds in the presence of a massless graviton, assuming the Regge behavior of the amplitude. Under this assumption, the problematic \(t\)-channel pole is canceled with the UV integral of the imaginary part of the amplitude in the dispersion relation, which gives rise to finite corrections to the positivity bounds. We find that low-energy effective field theories (EFT) with ``wrong'' sign are generically allowed. The allowed amount of the positivity violation is determined by the Regge behavior. This violation is suppressed by \({M}_{ \mathrm{pl}}^{-2}\alpha^{\prime}\) where \(\alpha \)' is the scale of Reggeization. This implies that the positivity bounds can be applied only when the cutoff scale of EFT is much lower than the scale of Reggeization. We then obtain the positivity bounds on scalar-tensor EFT at one-loop level. Implications of our results on the degenerate higher-order scalar-tensor (DHOST) theory are also discussed.Searching for surface defect CFTs within \( \mathrm{AdS}_3\).https://www.zbmath.org/1456.813732021-04-16T16:22:00+00:00"Faedo, Federico"https://www.zbmath.org/authors/?q=ai:faedo.federico"Lozano, Yolanda"https://www.zbmath.org/authors/?q=ai:lozano.yolanda"Petri, Nicolò"https://www.zbmath.org/authors/?q=ai:petri.nicoloSummary: We study \( \mathrm{AdS}_3 \times S^3 /{\mathbb{Z}}_k \times {\tilde{S}}^3/{\mathbb{Z}}_{k^{\prime}}\) solutions to M-theory preserving \(\mathcal{N} = (0, 4)\) supersymmetries, arising as near-horizon limits of M2-M5 brane intersections ending on M5'-branes, with both types of five-branes placed on A-type singularities. Solutions in this class asymptote locally to \( \mathrm{AdS}_7 /{\mathbb{Z}}_k\times{\tilde{S}}^3/{\mathbb{Z}}_{k^{\prime}} \), and can thus be interpreted as holographic duals to surface defect CFTs within the \(\mathcal{N} = (1, 0) 6\) d CFT dual to this solution. Upon reduction to Type IIA, we obtain a new class of solutions of the form \( \mathrm{AdS}_3 \times S^3/ \mathbb{Z}_k \times S^2 \times \Sigma_2\) preserving (0,4) supersymmetries. We construct explicit 2d quiver CFTs dual to these solutions, describing D2-D4 surface defects embedded within the 6d (1,0) quiver CFT dual to the \( \mathrm{AdS}_7/ \mathbb{Z}_k\) solution to massless IIA. Finally, in the massive case, we show that the recently constructed \( \mathrm{AdS}_3 \times S^2 \times \mathrm{CY}_2\) solutions with \(\mathcal{N} = (0, 4)\) supersymmetries gain a defect interpretation as surface CFTs originating from D2-NS5-D6 defects embedded within the 5d CFT dual to the Brandhuber-Oz \( \mathrm{AdS}_6\) background.Curvature properties of Kantowski-Sachs metric.https://www.zbmath.org/1456.530182021-04-16T16:22:00+00:00"Shaikh, Absos Ali"https://www.zbmath.org/authors/?q=ai:shaikh.absos-ali"Chakraborty, Dhyanesh"https://www.zbmath.org/authors/?q=ai:chakraborty.dhyaneshSummary: In this paper we have investigated the curvature restricted geometric properties of the generalized Kantowski-Sachs (briefly, GK-S) spacetime metric, a warped product of 2-dimensional base and 2-dimensional fibre. It is proved that GK-S metric describes a generalized Roter type, 2-quasi Einstein and \(Ein(3)\) manifold. It also has pseudosymmetric Weyl conformal tensor as well as conharmonic tensor and its conformal 2-forms are recurrent. Further, it realizes the curvature condition \(R\cdot R=Q(S,R)+\mathcal{L}(t,\theta)Q(g,C)\) (see, Theorem 4.1). We have also determined the curvature properties of Kantowski-Sachs (briefly, K-S), Bianchi type-III and Bianchi type-I metrics which are the special cases of GK-S spacetime metric. The sufficient condition under which GK-S metric represents a perfect fluid spacetime has also been obtained.Dynamic scale anomalous transport in QCD with electromagnetic background.https://www.zbmath.org/1456.814122021-04-16T16:22:00+00:00"Kawaguchi, Mamiya"https://www.zbmath.org/authors/?q=ai:kawaguchi.mamiya"Matsuzaki, Shinya"https://www.zbmath.org/authors/?q=ai:matsuzaki.shinya"Huang, Xu-Guang"https://www.zbmath.org/authors/?q=ai:huang.xu-guangSummary: We discuss phenomenological implications of the anomalous transport induced by the scale anomaly in QCD coupled to an electromagnetic (EM) field, based on a dilaton effective theory. The scale anomalous current emerges in a way perfectly analogous to the conformal transport current induced in a curved spacetime background, or the Nernst current in Dirac and Weyl semimetals --- both current forms are equivalent by a ``Weyl transformation''. We focus on a spatially homogeneous system of QCD hadron phase, which is expected to be created after the QCD phase transition and thermalization. We find that the EM field can induce a dynamic oscillatory dilaton field which in turn induces the scale anomalous current. As the phenomenological applications, we evaluate the dilepton and diphoton productions induced from the dynamic scale anomalous current, and find that those productions include a characteristic peak structure related to the dynamic oscillatory dilaton, which could be tested in heavy ion collisions. We also briefly discuss the out-of-equilibrium particle production created by a nonadiabatic dilaton oscillation, which happens in a way of the so-called tachyonic preheating mechanism.Twisted string theory in Anti-de Sitter space.https://www.zbmath.org/1456.814092021-04-16T16:22:00+00:00"Li, Songyuan"https://www.zbmath.org/authors/?q=ai:li.songyuan"Troost, Jan"https://www.zbmath.org/authors/?q=ai:troost.janSummary: We construct a string theory in three-dimensional Anti-de Sitter space-time that is independent of the boundary metric. It is a topologically twisted theory of quantum gravity. We study string theories with an asymptotic \(N = 2\) superconformal symmetry and demonstrate that, when the world sheet coupling to the space-time boundary metric undergoes a U(1) R-symmetry twist, the space-time boundary energy-momentum tensor becomes topological. As a by-product of our analysis, we obtain the world sheet vertex operator that codes the space-time energy-momentum for conformally flat boundary metrics.Holographic Floquet states in low dimensions.https://www.zbmath.org/1456.830772021-04-16T16:22:00+00:00"Garbayo, Ana"https://www.zbmath.org/authors/?q=ai:garbayo.ana"Mas, Javier"https://www.zbmath.org/authors/?q=ai:mas.javier"Ramallo, Alfonso V."https://www.zbmath.org/authors/?q=ai:ramallo.alfonso-vSummary: We study the response of a (2+1)-dimensional gauge theory to an external rotating electric field. In the strong coupling regime such system is formulated holographically in a top-down model constructed by intersecting D3- and D5-branes along 2+1 dimensions, in the quenched approximation, in which the D5-brane is a probe in the \(\mathrm{AdS}_5 \times {\mathbb{S}}^5\) geometry. The system has a non-equilibrium phase diagram with conductive and insulator phases. The external driving induces a rotating current due to vacuum polarization (in the insulator phase) and to Schwinger effect (in the conductive phase). For some particular values of the driving frequency the external field resonates with the vector mesons of the model and a rotating current can be produced even in the limit of vanishing driving field. These features are in common with the (3+1) dimensional setup based on the D3-D7 brane model and hint on some interesting universality. We also compute the conductivities paying special attention to the photovoltaic induced Hall effect, which is only present for massive charged carriers. In the vicinity of the Floquet condensate the optical Hall coefficient persists at zero driving field, signalling time reversal symmetry breaking.Nonrelativistic spinning strings.https://www.zbmath.org/1456.831072021-04-16T16:22:00+00:00"Roychowdhury, Dibakar"https://www.zbmath.org/authors/?q=ai:roychowdhury.dibakarSummary: We construct nonrelativistic spinning string solutions corresponding to \( \mathrm{SU} (1, 2|3)\) Spin-Matrix theory (SMT) limit of strings in \( \mathrm{AdS}_5 \times S^5\). Considering various nonrelativistic spinning string configurations both in \( \mathrm{AdS}_5\) as well as \(S^5\) we obtain corresponding dispersion relations in the strong coupling regime of SMT where the strong coupling \(( \sim \sqrt{\mathfrak{g}})\) corrections near the BPS bound have been estimated in the slow spinning limit of strings in \( \mathrm{AdS}_5\). We generalize our results explicitly by constructing three spin folded string configurations that has two of its spins along \( \mathrm{AdS}_5\) and one along \(S^5\). Our analysis reveals that the correction to the spectrum depends non trivially on the length of the NR string in \( \mathrm{AdS}_5\). The rest of the paper essentially unfolds the underlying connection between \( \mathrm{SU} (1, 2|3)\) Spin-Matrix theory (SMT) limit of strings in \( \mathrm{AdS}_5 \times S^5\) and the nonrelativistic Neumann-Rosochatius like integrable models in 1D. Taking two specific examples of NR spinning strings in \( R \times S^3\) as well as in certain sub-sector of \( \mathrm{AdS}_5\) we show that similar reduction is indeed possible where one can estimate the spectrum of the theory using 1D model.Gravitational Cardy limit and AdS black hole entropy.https://www.zbmath.org/1456.830402021-04-16T16:22:00+00:00"David, Marina"https://www.zbmath.org/authors/?q=ai:david.marina"Nian, Jun"https://www.zbmath.org/authors/?q=ai:nian.jun"Pando Zayas, Leopoldo A."https://www.zbmath.org/authors/?q=ai:pando-zayas.leopoldo-aSummary: We explore the gravitational implementation of the field theory Cardy-like limit recently used in the successful microstate countings of AdS black hole entropy in various dimensions. On the field theory side, the Cardy-like limit focuses on a particular scaling of conserved electric charges and angular momenta and we first translate this scaling to the gravitational side by a limiting procedure on the black hole parameters. We note that the scaling naturally accompanies a near-horizon region for which these black hole solutions are greatly simplified. Applying the Kerr/CFT correspondence to the near-horizon region, we precisely reproduce the Bekenstein-Hawking entropy of asymptotically \( \mathrm{AdS}_{4,5,6,7}\) BPS black holes. Our results explicitly provide a microscopic and universal low energy description for AdS black holes across various dimensions.A note on membrane interactions and the scalar potential.https://www.zbmath.org/1456.813352021-04-16T16:22:00+00:00"Herraez, Alvaro"https://www.zbmath.org/authors/?q=ai:herraez.alvaroSummary: We compute the tree-level potential between two parallel \(p\)-branes due to the exchange of scalars, gravitons and \((p+1)\)-forms. In the case of BPS membranes in 4d \(\mathcal{N} = 1\) supergravity, this provides an interesting reinterpretation of the classical Cremmer et al. formula for the F-term scalar potential in terms of scalar, graviton and 3-form exchange. In this way, we present a correspondence between the scalar potential at every point in scalar field space and a system of two interacting BPS membranes. This could potentially lead to interesting implications for the Swampland Program by providing a concrete way to relate conjectures about the form of scalar potentials with conjectures regarding the spectrum of charged objects.Petz map and Python's lunch.https://www.zbmath.org/1456.830322021-04-16T16:22:00+00:00"Zhao, Ying"https://www.zbmath.org/authors/?q=ai:zhao.yingSummary: We look at the interior operator reconstruction from the point of view of Petz map and study its complexity. We show that Petz maps can be written as precursors under the condition of perfect recovery. When we have the entire boundary system its complexity is related to the volume/action of the wormhole from the bulk operator to the boundary. When we only have access to part of the system, Python's lunch appears and its restricted complexity depends exponentially on the size of the subsystem one loses access to.From Hagedorn to Lee-Yang: partition functions of \(\mathcal{N} = 4\) SYM theory at finite \(N\).https://www.zbmath.org/1456.814372021-04-16T16:22:00+00:00"Kristensson, Alexander T."https://www.zbmath.org/authors/?q=ai:kristensson.alexander-t"Wilhelm, Matthias"https://www.zbmath.org/authors/?q=ai:wilhelm.matthiasSummary: We study the thermodynamics of the maximally supersymmetric Yang-Mills theory with gauge group \(\mathrm{U}(N\)) on \(\mathbb{R} \times S^3\), dual to type IIB superstring theory on \(\mathrm{AdS}_5 \times S^5\). While both theories are well-known to exhibit Hagedorn behavior at infinite \(N\), we find evidence that this is replaced by Lee-Yang behavior at large but finite \(N\): the zeros of the partition function condense into two arcs in the complex temperature plane that pinch the real axis at the temperature of the confinement-deconfinement transition. Concretely, we demonstrate this for the free theory via exact calculations of the (unrefined and refined) partition functions at \(N \leq 7\) for the \(\mathfrak{su} (2)\) sector containing two complex scalars, as well as at \(N \leq 5 \) for the \(\mathfrak{su} (2|3)\) sector containing 3 complex scalars and 2 fermions. In order to obtain these explicit results, we use a Molien-Weyl formula for arbitrary field content, utilizing the equivalence of the partition function with what is known to mathematicians as the Poincaré series of trace algebras of generic matrices. Via this Molien-Weyl formula, we also generate exact results for larger sectors.``Lagrangian disks'' in M-theory.https://www.zbmath.org/1456.814312021-04-16T16:22:00+00:00"Franco, Sebastían"https://www.zbmath.org/authors/?q=ai:franco.sebastian"Gukov, Sergei"https://www.zbmath.org/authors/?q=ai:gukov.sergei"Lee, Sangmin"https://www.zbmath.org/authors/?q=ai:lee.sangmin"Seong, Rak-Kyeong"https://www.zbmath.org/authors/?q=ai:seong.rak-kyeong"Sparks, James"https://www.zbmath.org/authors/?q=ai:sparks.jamesSummary: While the study of bordered (pseudo-)holomorphic curves with boundary on Lagrangian submanifolds has a long history, a similar problem that involves (special) Lagrangian submanifolds with boundary on complex surfaces appears to be largely overlooked in both physics and math literature. We relate this problem to geometry of coassociative submanifolds in \(G_2\) holonomy spaces and to Spin(7) metrics on 8-manifolds with \(T^2\) fibrations. As an application to physics, we propose a large class of brane models in type IIA string theory that generalize brane brick models on the one hand and 2d theories \(T[M_4]\) on the other.Comments on D3-brane holography.https://www.zbmath.org/1456.830732021-04-16T16:22:00+00:00"Chakraborty, Soumangsu"https://www.zbmath.org/authors/?q=ai:chakraborty.soumangsu"Giveon, Amit"https://www.zbmath.org/authors/?q=ai:giveon.amit"Kutasov, David"https://www.zbmath.org/authors/?q=ai:kutasov.davidSummary: We revisit the idea that the quantum dynamics of open strings ending on \(N\) D3-branes in the large \(N\) limit can be described at large `t Hooft coupling by classical closed string theory in the background created by the D3-branes in asymptotically flat spacetime. We study the resulting thermodynamics and compute the Hagedorn temperature and other properties of the D3-brane worldvolume theory in this regime. We also consider the theory in which the D3-branes are replaced by negative branes and show that its thermodynamics is well behaved. We comment on the idea that this theory can be thought of as an irrelevant deformation of \(\mathcal{N} = 4\) SYM, and on its relation to \(T\overline{T}\) deformed \( \mathrm{CFT}_2\).Generalized dualities and higher derivatives.https://www.zbmath.org/1456.830932021-04-16T16:22:00+00:00"Codina, Tomas"https://www.zbmath.org/authors/?q=ai:codina.tomas"Marqués, Diego"https://www.zbmath.org/authors/?q=ai:marques.diegoSummary: Generalized dualities had an intriguing incursion into Double Field Theory (DFT) in terms of local \(O(d,d)\) transformations. We review this idea and use the higher derivative formulation of DFT to compute the first order corrections to generalized dualities. Our main result is a unified expression that can be easily specified to any generalized T-duality (abelian, non-abelian, Poisson-Lie, etc.) or deformations such as Yang-Baxter, in any of the theories captured by the bi-parametric deformation (bosonic, heterotic strings and HSZ theory), in any supergravity scheme related by field redefinitions. The prescription allows further extensions to higher orders. As a check we recover some previously known particular examples.Black holes, moduli, and long-range forces.https://www.zbmath.org/1456.830412021-04-16T16:22:00+00:00"Heidenreich, Ben"https://www.zbmath.org/authors/?q=ai:heidenreich.benSummary: It is well known that an identical pair of extremal Reissner-Nordström black holes placed a large distance apart will exert no force on each other. In this paper, I establish that the same result holds in a very large class of two-derivative effective theories containing an arbitrary number of gauge fields and moduli, where the appropriate analog of an extremal Reissner-Nordström black hole is a charged, spherically symmetric black hole with vanishing surface gravity or vanishing horizon area. Analogous results hold for black branes.Edge modes of gravity. II: Corner metric and Lorentz charges.https://www.zbmath.org/1456.830242021-04-16T16:22:00+00:00"Freidel, Laurent"https://www.zbmath.org/authors/?q=ai:freidel.laurent"Geiller, Marc"https://www.zbmath.org/authors/?q=ai:geiller.marc"Pranzetti, Daniele"https://www.zbmath.org/authors/?q=ai:pranzetti.danieleSummary: In this second paper of the series we continue to spell out a new program for quantum gravity, grounded in the notion of corner symmetry algebra and its representations. Here we focus on tetrad gravity and its corner symplectic potential. We start by performing a detailed decomposition of the various geometrical quantities appearing in BF theory and tetrad gravity. This provides a new decomposition of the symplectic potential of BF theory and the simplicity constraints. We then show that the dynamical variables of the tetrad gravity corner phase space are the internal normal to the spacetime foliation, which is conjugated to the boost generator, and the corner coframe field. This allows us to derive several key results. First, we construct the corner Lorentz charges. In addition to sphere diffeomorphisms, common to all formulations of gravity, these charges add a local \(\mathfrak{sl} (2, \mathbb{C})\) component to the corner symmetry algebra of tetrad gravity. Second, we also reveal that the corner metric satisfies a local \(\mathfrak{sl} (2, \mathbb{R})\) algebra, whose Casimir corresponds to the corner area element. Due to the space-like nature of the corner metric, this Casimir belongs to the unitary discrete series, and its spectrum is therefore quantized. This result, which reconciles discreteness of the area spectrum with Lorentz invariance, is proven in the continuum and without resorting to a bulk connection. Third, we show that the corner phase space explains why the simplicity constraints become non-commutative on the corner. This fact requires a reconciliation between the bulk and corner symplectic structures, already in the classical continuum theory. Understanding this leads inevitably to the introduction of edge modes.
For Part I, see [the authors, J. High Energy Phys. 2020, No. 11, Paper No. 26, 51 p. (2020; Zbl 07326009)].The averaged null energy conditions in even dimensional curved spacetimes from AdS/CFT duality.https://www.zbmath.org/1456.830342021-04-16T16:22:00+00:00"Iizuka, Norihiro"https://www.zbmath.org/authors/?q=ai:iizuka.norihiro"Ishibashi, Akihiro"https://www.zbmath.org/authors/?q=ai:ishibashi.akihiro"Maeda, Kengo"https://www.zbmath.org/authors/?q=ai:maeda.kengoSummary: We consider averaged null energy conditions (ANEC) for strongly coupled quantum field theories in even (two and four) dimensional curved spacetimes by applying the no-bulk-shortcut principle in the context of the AdS/CFT duality. In the same context but in odd-dimensions, the present authors previously derived a conformally invariant averaged null energy condition (CANEC), which is a version of the ANEC with a certain weight function for conformal invariance. In even-dimensions, however, one has to deal with gravitational conformal anomalies, which make relevant formulas much more complicated than the odd-dimensional case. In two-dimensions, we derive the ANEC by applying the no-bulk-shortcut principle. In four-dimensions, we derive an inequality which essentially provides the lower-bound for the ANEC with a weight function. For this purpose, and also to get some geometric insights into gravitational conformal anomalies, we express the stress-energy formulas in terms of geometric quantities such as the expansions of boundary null geodesics and a quasi-local mass of the boundary geometry. We argue when the lowest bound is achieved and also discuss when the averaged value of the null energy can be negative, considering a simple example of a spatially compact universe with wormhole throat.Extremal black hole scattering at \(\mathcal{O} (G^3)\): graviton dominance, eikonal exponentiation, and differential equations.https://www.zbmath.org/1456.831172021-04-16T16:22:00+00:00"Parra-Martinez, Julio"https://www.zbmath.org/authors/?q=ai:parra-martinez.julio"Ruf, Michael S."https://www.zbmath.org/authors/?q=ai:ruf.michael-s"Zeng, Mao"https://www.zbmath.org/authors/?q=ai:zeng.maoSummary: We use \(\mathcal{N} = 8\) supergravity as a toy model for understanding the dynamics of black hole binary systems via the scattering amplitudes approach. We compute the conservative part of the classical scattering angle of two extremal (half-BPS) black holes with minimal charge misalignment at \(\mathcal{O} (G^3)\) using the eikonal approximation and effective field theory, finding agreement between both methods. We construct the massive loop integrands by Kaluza-Klein reduction of the known \(D\)-dimensional massless integrands. To carry out integration we formulate a novel method for calculating the post-Minkowskian expansion with exact velocity dependence, by solving velocity differential equations for the Feynman integrals subject to modified boundary conditions that isolate conservative contributions from the potential region. Motivated by a recent result for universality in massless scattering, we compare the scattering angle to the result found by \textit{Z. Bern} et al. [J. High Energy Phys. 2019, No. 10, Paper No. 206, 135 p. (2019; Zbl 1427.83035)] in Einstein gravity and find that they coincide in the high-energy limit, suggesting graviton dominance at this order.S matrix for a three-parameter integrable deformation of \( \mathrm{AdS}_3 \times S^3\) strings.https://www.zbmath.org/1456.814512021-04-16T16:22:00+00:00"Bocconcello, Marco"https://www.zbmath.org/authors/?q=ai:bocconcello.marco"Masuda, Isari"https://www.zbmath.org/authors/?q=ai:masuda.isari"Seibold, Fiona K."https://www.zbmath.org/authors/?q=ai:seibold.fiona-k"Sfondrini, Alessandro"https://www.zbmath.org/authors/?q=ai:sfondrini.alessandroSummary: We consider the three-parameter integrable deformation of the \( \mathrm{AdS}_3 \times S^3\) superstring background constructed in [\textit{F. Delduc} et al., J. High Energy Phys. 2019, No. 1, Paper No. 109, 25 p. (2019; Zbl 1414.81129)]. Working on the string worldsheet in uniform lightcone gauge, we find the tree-level bosonic S matrix of the model and study some of its limits.Sigma models with local couplings: a new integrability-RG flow connection.https://www.zbmath.org/1456.831022021-04-16T16:22:00+00:00"Hoare, Ben"https://www.zbmath.org/authors/?q=ai:hoare.ben"Levine, Nat"https://www.zbmath.org/authors/?q=ai:levine.nat"Tseytlin, Arkady A."https://www.zbmath.org/authors/?q=ai:tseytlin.arkady-aSummary: We consider several classes of \(\sigma \)-models (on groups and symmetric spaces, \( \eta \)-models, \( \lambda \)-models) with local couplings that may depend on the 2d coordinates, e.g. on time \(\tau \). We observe that (i) starting with a classically integrable 2d \(\sigma \)-model, (ii) formally promoting its couplings \(h_\alpha\) to functions \(h_\alpha(\tau) \) of 2d time, and (iii) demanding that the resulting time-dependent model also admits a Lax connection implies that \(h_\alpha(\tau)\) must solve the 1-loop RG equations of the original theory with \(\tau\) interpreted as RG time. This provides a novel example of an `integrability-RG flow' connection. The existence of a Lax connection suggests that these time-dependent \(\sigma \)-models may themselves be understood as integrable. We investigate this question by studying the possibility of constructing non-local and local conserved charges. Such \(\sigma \)-models with \(D\)-dimensional target space and time-dependent couplings subject to the RG flow naturally appear in string theory upon fixing the light-cone gauge in a \((D + 2)\)-dimensional conformal \(\sigma \)-model with a metric admitting a covariantly constant null Killing vector and a dilaton linear in the null coordinate.Curvature constraints in heterotic Landau-Ginzburg models.https://www.zbmath.org/1456.830992021-04-16T16:22:00+00:00"Garavuso, Richard S."https://www.zbmath.org/authors/?q=ai:garavuso.richard-sSummary: In this paper, we study a class of heterotic Landau-Ginzburg models. We show that the action can be written as a sum of BRST-exact and non-exact terms. The non-exact terms involve the pullback of the complexified Kähler form to the worldsheet and terms arising from the superpotential, which is a Grassmann-odd holomorphic function of the superfields. We then demonstrate that the action is invariant on-shell under supersymmetry transformations up to a total derivative. Finally, we extend the analysis to the case in which the superpotential is not holomorphic. In this case, we find that supersymmetry imposes a constraint which relates the nonholomorphic parameters of the superpotential to the Hermitian curvature. Various special cases of this constraint have previously been used to establish properties of Mathai-Quillen form analogues which arise in the corresponding heterotic Landau-Ginzburg models. There, it was claimed that supersymmetry imposes those constraints. Our goal in this paper is to support that claim. The analysis for the nonholomorphic case also reveals a constraint imposed by supersymmetry that we did not anticipate from studies of Mathai-Quillen form analogues.The Regge limit of \( \mathrm{AdS}_3\) holographic correlators.https://www.zbmath.org/1456.830792021-04-16T16:22:00+00:00"Giusto, Stefano"https://www.zbmath.org/authors/?q=ai:giusto.stefano"Hughes, Marcel R. R."https://www.zbmath.org/authors/?q=ai:hughes.marcel-r-r"Russo, Rodolfo"https://www.zbmath.org/authors/?q=ai:russo.rodolfoSummary: We study the Regge limit of 4-point \( \mathrm{AdS}_3 \times S^3\) correlators in the tree-level supergravity approximation and provide various explicit checks of the relation between the eikonal phase derived in the bulk picture and the anomalous dimensions of certain double-trace operators. We consider both correlators involving all light operators and HHLL correlators with two light and two heavy multi-particle states. These heavy operators have a conformal dimension proportional to the central charge and are pure states of the theory, dual to asymptotically \( \mathrm{AdS}_3 \times S^3\) regular geometries. Deviation from \( \mathrm{AdS}_3 \times S^3\) is parametrised by a scale \(\mu\) and is related to the conformal dimension of the dual heavy operator. In the HHLL case, we work at leading order in \(\mu\) and derive the CFT data relevant to the bootstrap relations in the Regge limit. Specifically, we show that the minimal solution to these equations relevant for the conical defect geometries is different to the solution implied by the microstate geometries dual to pure states.Modular invariance in superstring theory from \(\mathcal{N} = 4\) super-Yang-Mills.https://www.zbmath.org/1456.814242021-04-16T16:22:00+00:00"Chester, Shai M."https://www.zbmath.org/authors/?q=ai:chester.shai-m"Green, Michael B."https://www.zbmath.org/authors/?q=ai:green.michael-b"Pufu, Silviu S."https://www.zbmath.org/authors/?q=ai:pufu.silviu-s"Wang, Yifan"https://www.zbmath.org/authors/?q=ai:wang.yifan"Wen, Congkao"https://www.zbmath.org/authors/?q=ai:wen.congkaoSummary: We study the four-point function of the lowest-lying half-BPS operators in the \(\mathcal{N} = 4\) \( \mathrm{SU} (N)\) super-Yang-Mills theory and its relation to the flat-space four-graviton amplitude in type IIB superstring theory. We work in a large-\(N\) expansion in which the complexified Yang-Mills coupling \(\tau\) is fixed. In this expansion, non-perturbative instanton contributions are present, and the \( \mathrm{SL} (2, \mathbb{Z})\) duality invariance of correlation functions is manifest. Our results are based on a detailed analysis of the sphere partition function of the mass-deformed SYM theory, which was previously computed using supersymmetric localization. This partition function determines a certain integrated correlator in the undeformed \(\mathcal{N} = 4\) SYM theory, which in turn constrains the four-point correlator at separated points. In a normalization where the two-point functions are proportional to \(N^2- 1\) and are independent of \(\tau\) and \(\overline{\tau} \), we find that the terms of order \(\sqrt{N}\) and \(1/\sqrt{N}\) in the large \(N\) expansion of the four-point correlator are proportional to the non-holomorphic Eisenstein series \(E\left(\frac{3}{2},\tau, \overline{\tau}\right)\) and \(E\left(\frac{5}{2},\tau, \overline{\tau}\right) \), respectively. In the flat space limit, these terms match the corresponding terms in the type IIB S-matrix arising from \(R^4\) and \(D^4R^4\) contact interactions, which, for the \(R^4\) case, represents a check of AdS/CFT at finite string coupling. Furthermore, we present striking evidence that these results generalize so that, at order \({N}^{\frac{1}{2}-m}\) with integer \(m \geq 0 \), the expansion of the integrated correlator we study is a linear sum of non-holomorphic Eisenstein series with half-integer index, which are manifestly \( \mathrm{SL} (2, \mathbb{Z})\) invariant.Gravitational dual of averaged free CFT's over the Narain lattice.https://www.zbmath.org/1456.830302021-04-16T16:22:00+00:00"Pérez, Alfredo"https://www.zbmath.org/authors/?q=ai:perez.alfredo"Troncoso, Ricardo"https://www.zbmath.org/authors/?q=ai:troncoso.ricardoSummary: It has been recently argued that the averaging of free CFT's over the Narain lattice can be holographically described through a Chern-Simons theory for \( \mathrm{U} (1)^D \times \mathrm{U}(1)^D\) with a precise prescription to sum over three-dimensional handlebodies. We show that a gravitational dual of these averaged CFT's would be provided by Einstein gravity on \( \mathrm{AdS}_3\) with \( \mathrm{U} (1)^{ D - 1}\times \mathrm{ U} (1)^{ D- 1}\) gauge fields, endowed with a precise set of boundary conditions closely related to the ``soft hairy'' ones. Gravitational excitations then go along diagonal \( \mathrm{SL} (2, \mathbb{R})\) generators, so that the asymptotic symmetries are spanned by \( \mathrm{U} (1)^D \times \mathrm{U} (1)^D\) currents. The stress-energy tensor can then be geometrically seen as composite of these currents through a twisted Sugawara construction. Our boundary conditions are such that for the reduced phase space, there is a one-to-one map between the configurations in the gravitational and the purely abelian theories. The partition function in the bulk could then also be performed either from a non-abelian Chern-Simons theory for two copies of \( \mathrm{SL} (2, \mathbb{R}) \times \mathrm{U} (1)^{ D- 1}\) generators, or formally through a path integral along the family of allowed configurations for the metric. The new boundary conditions naturally accommodate BTZ black holes, and the microscopic number of states then appears to be manifestly positive and suitably accounted for from the partition function in the bulk. The inclusion of higher spin currents through an extended twisted Sugawara construction in the context of higher spin gravity is also briefly addressed.Probing the Planck scale: the modification of the time evolution operator due to the quantum structure of spacetime.https://www.zbmath.org/1456.830292021-04-16T16:22:00+00:00"Padmanabhan, T."https://www.zbmath.org/authors/?q=ai:padmanabhan.t-v|padmanabhan.thanuSummary: The propagator which evolves the wave-function in non-relativistic quantum mechanics, can be expressed as a matrix element of a time evolution operator: i.e. \(G_{ \mathrm{NR}}(x) = \langle \mathbf{x}_2|U_{ \mathrm{NR}}(t)|\mathbf{x}_1 \rangle \) in terms of the orthonormal eigenkets \( | \mathbf{x} \rangle \) of the position operator. In quantum field theory, it is not possible to define a conceptually useful single-particle position operator or its eigenkets. It is also not possible to interpret the relativistic (Feynman) propagator \(G_R(x)\) as evolving any kind of single-particle wave-functions. In spite of all these, it is indeed possible to express the propagator of a free spinless particle, in quantum field theory, as a matrix element \( \langle \mathbf{x}_2|U_R(t)|\mathbf{x}_1 \rangle \) for a suitably defined time evolution operator and (non-orthonormal) kets \( | \mathbf{x} \rangle \) labeled by spatial coordinates. At mesoscopic scales, which are close but not too close to Planck scale, one can incorporate quantum gravitational corrections to the propagator by introducing a zero-point-length. It turns out that even this quantum-gravity-corrected propagator can be expressed as a matrix element \( \langle \mathbf{x}_2 | U_{ \mathrm{QG}}(t)|\mathbf{x}_1 \rangle \). I describe these results and explore several consequences. It turns out that the evolution operator \(U_{ \mathrm{QG}}(t)\) becomes non-unitary for sub-Planckian time intervals while remaining unitary for time interval is larger than Planck time. The results can be generalized to any ultrastatic curved spacetime.A novel quantum-mechanical interpretation of the Dirac equation.https://www.zbmath.org/1456.810142021-04-16T16:22:00+00:00"Kiessling, M. K-H"https://www.zbmath.org/authors/?q=ai:kiessling.michael-karl-heinz"Tahvildar-Zadeh, A. S."https://www.zbmath.org/authors/?q=ai:tahvildar-zadeh.a-shadiEnhanced corrections near holographic entanglement transitions: a chaotic case study.https://www.zbmath.org/1456.830742021-04-16T16:22:00+00:00"Dong, Xi"https://www.zbmath.org/authors/?q=ai:dong.xi"Wang, Huajia"https://www.zbmath.org/authors/?q=ai:wang.huajiaSummary: Recent work found an enhanced correction to the entanglement entropy of a subsystem in a chaotic energy eigenstate. The enhanced correction appears near a phase transition in the entanglement entropy that happens when the subsystem size is half of the entire system size. Here we study the appearance of such enhanced corrections holo-graphically. We show explicitly how to find these corrections in the example of chaotic eigenstates by summing over contributions of all bulk saddle point solutions, including those that break the replica symmetry. With the help of an emergent rotational symmetry, the sum over all saddle points is written in terms of an effective action for cosmic branes. The resulting Renyi and entanglement entropies are then naturally organized in a basis of fixed-area states and can be evaluated directly, showing an enhanced correction near holographic entanglement transitions. We comment on several intriguing features of our tractable example and discuss the implications for finding a convincing derivation of the enhanced corrections in other, more general holographic examples.The first law of differential entropy and holographic complexity.https://www.zbmath.org/1456.830842021-04-16T16:22:00+00:00"Sarkar, Debajyoti"https://www.zbmath.org/authors/?q=ai:sarkar.debajyoti"Visser, Manus"https://www.zbmath.org/authors/?q=ai:visser.manus-rSummary: We construct the CFT dual of the first law of spherical causal diamonds in three-dimensional AdS spacetime. A spherically symmetric causal diamond in \( \mathrm{AdS}_3\) is the domain of dependence of a spatial circular disk with vanishing extrinsic curvature. The bulk first law relates the variations of the area of the boundary of the disk, the spatial volume of the disk, the cosmological constant and the matter Hamiltonian. In this paper we specialize to first-order metric variations from pure AdS to the conical defect spacetime, and the bulk first law is derived following a coordinate based approach. The AdS/CFT dictionary connects the area of the boundary of the disk to the differential entropy in \( \mathrm{CFT}_2\), and assuming the `complexity=volume' conjecture, the volume of the disk is considered to be dual to the complexity of a cutoff CFT. On the CFT side we explicitly compute the differential entropy and holographic complexity for the vacuum state and the excited state dual to conical AdS using the kinematic space formalism. As a result, the boundary dual of the bulk first law relates the first-order variations of differential entropy and complexity to the variation of the scaling dimension of the excited state, which corresponds to the matter Hamiltonian variation in the bulk. We also include the variation of the central charge with associated chemical potential in the boundary first law. Finally, we comment on the boundary dual of the first law for the Wheeler-deWitt patch of AdS, and we propose an extension of our CFT first law to higher dimensions.Emergent Yang-Mills theory.https://www.zbmath.org/1456.830202021-04-16T16:22:00+00:00"de Mello Koch, Robert"https://www.zbmath.org/authors/?q=ai:de-mello-koch.robert"Huang, Jia-Hui"https://www.zbmath.org/authors/?q=ai:huang.jiahui"Kim, Minkyoo"https://www.zbmath.org/authors/?q=ai:kim.minkyoo"Van Zyl, Hendrik J. R."https://www.zbmath.org/authors/?q=ai:van-zyl.hendrik-j-rSummary: We study the spectrum of anomalous dimensions of operators dual to giant graviton branes. The operators considered belong to the \(\mathrm{su} (2|3)\) sector of \(\mathcal{N} = 4\) super Yang-Mills theory, have a bare dimension \(\sim N\) and are a linear combination of restricted Schur polynomials with \(p \sim O(1)\) long rows or columns. In the same way that the operator mixing problem in the planar limit can be mapped to an integrable spin chain, we find that our problems maps to particles hopping on a lattice. The detailed form of the model is in precise agreement with the expected world volume dynamics of \(p\) giant graviton branes, which is a \(\mathrm{U} (p)\) Yang-Mills theory. The lattice model we find has a number of noteworthy features. It is a lattice model with all-to-all sites interactions and quenched disorder.T duality and Wald entropy formula in the Heterotic Superstring effective action at first-order in \(\alpha '\).https://www.zbmath.org/1456.830972021-04-16T16:22:00+00:00"Elgood, Zachary"https://www.zbmath.org/authors/?q=ai:elgood.zachary"Ortín, Tomás"https://www.zbmath.org/authors/?q=ai:ortin.tomasSummary: We consider the compactification on a circle of the Heterotic Superstring effective action to first order in the Regge slope parameter \(\alpha '\) and re-derive the \(\alpha '\)-corrected Buscher rules first found in [\textit{E. Bergshoeff} et al., Classical Quantum Gravity 13, No. 3, 321--343 (1996; Zbl 0849.53074)], proving the T duality invariance of the dimensionally-reduced action to that order in \(\alpha '\). We use Iyer and Wald's prescription to derive an entropy formula that can be applied to black hole solutions which can be obtained by a single non-trivial compactification on a circle and discuss its invariance under the \(\alpha '\)-corrected T duality transformations. This formula has been successfully applied to \(\alpha '\)-corrected 4-dimensional non-extremal Reissner-Nordström black holes in [\textit{P. A. Cano} et al., J. High Energy Phys. 2020, No. 2, Paper No. 31, 31 p. (2020; Zbl 1435.83077)] and we apply it here to a heterotic version of the Strominger-Vafa 5-dimensional extremal black hole.Renormalization group flow of Chern-Simons boundary conditions and generalized Ricci tensor.https://www.zbmath.org/1456.813172021-04-16T16:22:00+00:00"Pulmann, Ján"https://www.zbmath.org/authors/?q=ai:pulmann.jan"Ševera, Pavol"https://www.zbmath.org/authors/?q=ai:severa.pavol"Youmans, Donald R."https://www.zbmath.org/authors/?q=ai:youmans.donald-rSummary: We find a Chern-Simons propagator on the ball with the chiral boundary condition. We use it to study perturbatively Chern-Simons boundary conditions related to 2-dim \(\sigma\)-models and to Poisson-Lie T-duality. In particular, we find their renormalization group flow, given by the generalized Ricci tensor. Finally we briefly discuss what happens when the Chern-Simons theory is replaced by a Courant \(\sigma\)-model or possibly by a more general AKSZ model.Two-sided conformally recurrent self-dual spaces.https://www.zbmath.org/1456.530602021-04-16T16:22:00+00:00"Chudecki, Adam"https://www.zbmath.org/authors/?q=ai:chudecki.adamSummary: Two-sided conformally recurrent 4-dimensional self-dual spaces are considered. It is shown that such spaces are equipped with nonexpanding congruences of null strings. The general structure of weak nonexpanding hyperheavenly spaces is given. Finally, the general metrics of Petrov-Penrose type \([\text{D}]\otimes[-]\) spaces are presented.Symmetries at null boundaries: two and three dimensional gravity cases.https://www.zbmath.org/1456.830532021-04-16T16:22:00+00:00"Adami, H."https://www.zbmath.org/authors/?q=ai:adami.hamed"Sheikh-Jabbari, M. M."https://www.zbmath.org/authors/?q=ai:sheikh-jabbari.mohammad-mahdi"Taghiloo, V."https://www.zbmath.org/authors/?q=ai:taghiloo.v"Yavartanoo, H."https://www.zbmath.org/authors/?q=ai:yavartanoo.hossein"Zwikel, C."https://www.zbmath.org/authors/?q=ai:zwikel.celineSummary: We carry out in full generality and without fixing specific boundary conditions, the symmetry and charge analysis near a generic null surface for two and three dimensional \((2d\) and \(3d)\) gravity theories. In \(2d\) and \(3d\) there are respectively two and three charges which are generic functions over the codimension one null surface. The integrability of charges and their algebra depend on the state-dependence of symmetry generators which is a priori not specified. We establish the existence of infinitely many choices that render the surface charges integrable. We show that there is a choice, the ``fundamental basis'', where the null boundary symmetry algebra is the \(\mathrm{Heisenberg} \oplus \mathrm{Diff}(d - 2)\) algebra. We expect this result to be true for \(d > 3\) when there is no Bondi news through the null surface.Quantum gases and white dwarfs with quantum gravity.https://www.zbmath.org/1456.830512021-04-16T16:22:00+00:00"Moussa, Mohamed"https://www.zbmath.org/authors/?q=ai:moussa.mohamedThermal dynamic phase transition of Reissner-Nordström Anti-de Sitter black holes on free energy landscape.https://www.zbmath.org/1456.830442021-04-16T16:22:00+00:00"Li, Ran"https://www.zbmath.org/authors/?q=ai:li.ran"Zhang, Kun"https://www.zbmath.org/authors/?q=ai:zhang.kun"Wang, Jin"https://www.zbmath.org/authors/?q=ai:wang.jinSummary: We explore the thermodynamics and the underlying kinetics of the van der Waals type phase transition of Reissner-Nordström anti-de Sitter (RNAdS) black holes based on the free energy landscape. We show that the thermodynamic stabilities of the three branches of the RNAdS black holes are determined by the underlying free energy landscape topography. We suggest that the large (small) RNAdS black hole can have the probability to switch to the small (large) black hole due to the thermal fluctuation. Such a state switching process under the thermal fluctuation is taken as a stochastic process and the associated kinetics can be described by the probabilistic Fokker-Planck equation. We obtained the time dependent solutions for the probabilistic evolution by numerically solving Fokker-Planck equation with the reflecting boundary conditions. We also investigated the first passage process which describes how fast a system undergoes a stochastic process for the first time. The distributions of the first passage time switching from small (large) to large (small) black hole and the corresponding mean first passage time as well as its fluctuations at different temperatures are studied in detail. We conclude that the mean first passage time and its fluctuations are related to the free energy landscape topography through barrier heights and temperatures.Gravitational duals to the grand canonical ensemble abhor Cauchy horizons.https://www.zbmath.org/1456.830802021-04-16T16:22:00+00:00"Hartnoll, Sean A."https://www.zbmath.org/authors/?q=ai:hartnoll.sean-a"Horowitz, Gary T."https://www.zbmath.org/authors/?q=ai:horowitz.gary-t"Kruthoff, Jorrit"https://www.zbmath.org/authors/?q=ai:kruthoff.jorrit"Santos, Jorge E."https://www.zbmath.org/authors/?q=ai:santos.jorge-eSummary: The gravitational dual to the grand canonical ensemble of a large \(N\) holographic theory is a charged black hole. These spacetimes -- for example Reissner-Nordström-AdS -- can have Cauchy horizons that render the classical gravitational dynamics of the black hole interior incomplete. We show that a (spatially uniform) deformation of the CFT by a neutral scalar operator generically leads to a black hole with no inner horizon. There is instead a spacelike Kasner singularity in the interior. For relevant deformations, Cauchy horizons never form. For certain irrelevant deformations, Cauchy horizons can exist at one specific temperature. We show that the scalar field triggers a rapid collapse of the Einstein-Rosen bridge at the would-be Cauchy horizon. Finally, we make some observations on the interior of charged dilatonic black holes where the Kasner exponent at the singularity exhibits an attractor mechanism in the low temperature limit.Integrable deformation of \(\mathbb{CP}^n\) and generalised Kähler geometry.https://www.zbmath.org/1456.812292021-04-16T16:22:00+00:00"Demulder, Saskia"https://www.zbmath.org/authors/?q=ai:demulder.saskia"Hassler, Falk"https://www.zbmath.org/authors/?q=ai:hassler.falk"Piccinini, Giacomo"https://www.zbmath.org/authors/?q=ai:piccinini.giacomo"Thompson, Daniel C."https://www.zbmath.org/authors/?q=ai:thompson.daniel-cSummary: We build on the results of [the authors, ibid. 2020, No. 9, Paper No. 44, 25 p. (2020; Zbl 1454.81103)] for generalised frame fields on generalised quotient spaces and study integrable deformations for \(\mathbb{CP}^n\). In particular we show how, when the target space of the Principal Chiral Model is a complex projective space, a two-parameter deformation can be introduced in principle. The second parameter can however be removed via a diffeomorphism, which we construct explicitly, in accordance with the results stemming from a thorough integrability analysis we carry out. We also elucidate how the deformed target space can be seen as an instance of generalised Kähler, or equivalently bi-Hermitian, geometry. In this respect, we find the generic form of the pure spinors for \(\mathbb{CP}^n\) and the explicit expression for the generalised Kähler potential for \(n = 1, 2\).Some specific wormhole solutions in \(f(R)\)-modified gravity theory.https://www.zbmath.org/1456.830642021-04-16T16:22:00+00:00"Ghosh, Bikram"https://www.zbmath.org/authors/?q=ai:ghosh.bikram"Mitra, Saugata"https://www.zbmath.org/authors/?q=ai:mitra.saugata"Chakraborty, Subenoy"https://www.zbmath.org/authors/?q=ai:chakraborty.subenoyComplexified quasinormal modes and the pole-skipping in a holographic system at finite chemical potential.https://www.zbmath.org/1456.830722021-04-16T16:22:00+00:00"Abbasi, Navid"https://www.zbmath.org/authors/?q=ai:abbasi.navid"Tahery, Sara"https://www.zbmath.org/authors/?q=ai:tahery.saraSummary: We develop a method to study coupled dynamics of gauge-invariant variables, constructed out of metric and gauge field fluctuations on the background of a \(\mathrm{AdS}_5\) Reissner-Nordström black brane. Using this method, we compute the numerical spectrum of quasinormal modes associated with fluctuations of spin 0, 1 and 2, non-perturbatively in \(\mu /T\). We also analytically compute the spectrum of hydrodynamic excitations in the small chemical potential limit. Then, by studying the spectral curve at complex momenta in every spin channel, we numerically find points at which hydrodynamic and non-hydrodynamic poles collide. We discuss the relation between such collision points and the convergence radius of the hydrodynamic derivative expansion. Specifically in the spin 0 channel, we find that within the range \(1.1 \lesssim \mu /T \lesssim 2\), the radius of convergence of the hydrodynamic sound mode is set by the absolute value of the complex momentum corresponding to the point at which the sound pole collides with the hydrodynamic diffusion pole. It shows that in holographic systems at finite chemical potential, the convergence of the hydrodynamic derivative expansion in the mentioned range is fully controlled by hydrodynamic information. As the last result, we explicitly show that the relevant information about quantum chaos in our system can be extracted from the pole-skipping points of energy density response function. We find a threshold value for \(\mu /T\), lower than which the pole-skipping points can be computed perturbatively in a derivative expansion.Sharp asymptotics for the solutions of the three-dimensional massless Vlasov-Maxwell system with small data.https://www.zbmath.org/1456.351912021-04-16T16:22:00+00:00"Bigorgne, Léo"https://www.zbmath.org/authors/?q=ai:bigorgne.leoSummary: This paper is concerned with the asymptotic properties of the small data solutions to the massless Vlasov-Maxwell system in \(3d\). We use vector field methods to derive almost optimal decay estimates in null directions for the electromagnetic field, the particle density and their derivatives. No compact support assumption in \(x\) or \(v\) is required on the initial data, and the decay in \(v\) is in particular initially optimal. Consistently with Proposition 8.1 of \textit{L. Bigorgne} [``Asymptotic properties of small data solutions of the Vlasov-Maxwell system in high dimensions'', Preprint, \url{arXiv:1712.09698}], the Vlasov field is supposed to vanish initially for small velocities. In order to deal with the slow decay rate of the solutions near the light cone and to prove that the velocity support of the particle density remains bounded away from 0, we make crucial use of the null properties of the system.Aharonov-Bohm superselection sectors.https://www.zbmath.org/1456.812972021-04-16T16:22:00+00:00"Dappiaggi, Claudio"https://www.zbmath.org/authors/?q=ai:dappiaggi.claudio"Ruzzi, Giuseppe"https://www.zbmath.org/authors/?q=ai:ruzzi.giuseppe"Vasselli, Ezio"https://www.zbmath.org/authors/?q=ai:vasselli.ezioSummary: We show that the Aharonov-Bohm effect finds a natural description in the setting of QFT on curved spacetimes in terms of superselection sectors of local observables. The extension of the analysis of superselection sectors from Minkowski spacetime to an arbitrary globally hyperbolic spacetime unveils the presence of a new quantum number labelling charged superselection sectors. In the present paper, we show that this ``topological'' quantum number amounts to the presence of a background flat potential which rules the behaviour of charges when transported along paths as in the Aharonov-Bohm effect. To confirm these abstract results, we quantize the Dirac field in the presence of a background flat potential and show that the Aharonov-Bohm phase gives an irreducible representation of the fundamental group of the spacetime labelling the charged sectors of the Dirac field. We also show that non-abelian generalizations of this effect are possible only on spacetimes with a non-abelian fundamental group.Propagators, BCFW recursion and new scattering equations at one loop.https://www.zbmath.org/1456.814522021-04-16T16:22:00+00:00"Farrow, Joseph A."https://www.zbmath.org/authors/?q=ai:farrow.joseph-a"Geyer, Yvonne"https://www.zbmath.org/authors/?q=ai:geyer.yvonne"Lipstein, Arthur E."https://www.zbmath.org/authors/?q=ai:lipstein.arthur-e"Monteiro, Ricardo"https://www.zbmath.org/authors/?q=ai:monteiro.ricardo"Stark-Muchão, Ricardo"https://www.zbmath.org/authors/?q=ai:stark-muchao.ricardoSummary: We investigate how loop-level propagators arise from tree level via a forward-limit procedure in two modern approaches to scattering amplitudes, namely the BCFW recursion relations and the scattering equations formalism. In the first part of the paper, we revisit the BCFW construction of one-loop integrands in momentum space, using a convenient parametrisation of the \(D\)-dimensional loop momentum. We work out explicit examples with and without supersymmetry, and discuss the non-planar case in both gauge theory and gravity. In the second part of the paper, we study an alternative approach to one-loop integrands, where these are written as worldsheet formulas based on new one-loop scattering equations. These equations, which are inspired by BCFW, lead to standard Feynman-type propagators, instead of the `linear'-type loop-level propagators that first arose from the formalism of ambitwistor strings. We exploit the analogies between the two approaches, and present a proof of an all-multiplicity worldsheet formula using the BCFW recursion.On the impact of Majorana masses in gravity-matter systems.https://www.zbmath.org/1456.830192021-04-16T16:22:00+00:00"de Brito, Gustavo P."https://www.zbmath.org/authors/?q=ai:de-brito.gustavo-p"Hamada, Yuta"https://www.zbmath.org/authors/?q=ai:hamada.yuta"Pereira, Antonio D."https://www.zbmath.org/authors/?q=ai:pereira.antonio-d"Yamada, Masatoshi"https://www.zbmath.org/authors/?q=ai:yamada.masatoshiAn asymptotically safe quantum theory of gravity goes beyond the standard perturbative paradigm. It relies on the existence of a non-trivial UV fixed point that features finitely many relevant directions, corresponding to the number of free parameters to be fixed by experiments. Within this scenario, coupling Standard Model matter degrees to quantum gravity, recent works have managed to explain observed quantities in the low energy regimes by assuming the existence of an asymptotically safe fixed point. In the present work, using the functional renormalization group, the authors ``aim at giving the first steps to investigate the quantum-gravity fluctuations effects to the seesaw mechanism'' -- a mechanism grounded on the introduction of a right-handed neutrino with a Majorana mass term which couples to the left-handed neutrino and the Higgs through a Yukawa interaction. It is worked ``within a specific truncation for the effective average action and with particular choices for gauge parameters, regulators and field parametrizations''. The main findings concern quantum gravity effects on the running of the Majorana masses and the impact of Majorana masses on the running of the Higgs-Majorana couplings. The authors state: ``The system considered in this paper can be regarded as a toy model motivated by neutrino physics.''
Reviewer: Horst-Heino von Borzeszkowski (Berlin)Euclidean black saddles and \(\mathrm{AdS}_4\) black holes.https://www.zbmath.org/1456.830382021-04-16T16:22:00+00:00"Bobev, Nikolay"https://www.zbmath.org/authors/?q=ai:bobev.nokolai"Charles, Anthony M."https://www.zbmath.org/authors/?q=ai:charles.anthony-m"Min, Vincent S."https://www.zbmath.org/authors/?q=ai:min.vincent-sSummary: We find new asymptotically locally \(\mathrm{AdS}_4\) Euclidean supersymmetric solutions of the STU model in four-dimensional gauged supergravity. These ``black saddles'' have an \(S^1 \times {\Sigma}_{\mathfrak{g}}\) boundary at asymptotic infinity and cap off smoothly in the interior. The solutions can be uplifted to eleven dimensions and are holographically dual to the topologically twisted ABJM theory on \(S^1 \times {\Sigma}_{\mathfrak{g}}\). We show explicitly that the on-shell action of the black saddle solutions agrees exactly with the topologically twisted index of the ABJM theory in the planar limit for general values of the magnetic fluxes, flavor fugacities, and real masses. This agreement relies on a careful holographic renormalization analysis combined with a novel UV/IR holographic relation between supergravity parameters and field theory sources. The Euclidean black saddle solution space contains special points that can be Wick-rotated to regular Lorentzian supergravity backgrounds that correspond to the well-known supersymmetric dyonic \(\mathrm{AdS}_4\) black holes in the STU model.Bootstrap bounds on closed Einstein manifolds.https://www.zbmath.org/1456.830852021-04-16T16:22:00+00:00"Bonifacio, James"https://www.zbmath.org/authors/?q=ai:bonifacio.james"Hinterbichler, Kurt"https://www.zbmath.org/authors/?q=ai:hinterbichler.kurtSummary: A compact Riemannian manifold is associated with geometric data given by the eigenvalues of various Laplacian operators on the manifold and the triple overlap integrals of the corresponding eigenmodes. This geometric data must satisfy certain consistency conditions that follow from associativity and the completeness of eigenmodes. We show that it is possible to obtain nontrivial bounds on the geometric data of closed Einstein manifolds by using semidefinite programming to study these consistency conditions, in analogy to the conformal bootstrap bounds on conformal field theories. These bootstrap bounds translate to constraints on the tree-level masses and cubic couplings of Kaluza-Klein modes in theories with compact extra dimensions. We show that in some cases the bounds are saturated by known manifolds.The Hamilton-Jacobi equation and holographic renormalization group flows on sphere.https://www.zbmath.org/1456.830822021-04-16T16:22:00+00:00"Kim, Nakwoo"https://www.zbmath.org/authors/?q=ai:kim.nakwoo"Kim, Se-Jin"https://www.zbmath.org/authors/?q=ai:kim.se-jinSummary: We study the Hamilton-Jacobi formulation of effective mechanical actions associated with holographic renormalization group flows when the field theory is put on the sphere and mass terms are turned on. Although the system is supersymmetric and it is described by a superpotential, Hamilton's characteristic function is not readily given by the superpotential when the boundary of AdS is curved. We propose a method to construct the solution as a series expansion in scalar field degrees of freedom. The coefficients are functions of the warp factor to be determined by a differential equation one obtains when the ansatz is substituted into the Hamilton-Jacobi equation. We also show how the solution can be derived from the BPS equations without having to solve differential equations. The characteristic function readily provides information on holographic counterterms which cancel divergences of the on-shell action near the boundary of AdS.A nonabelian M5 brane Lagrangian in a supergravity background.https://www.zbmath.org/1456.831142021-04-16T16:22:00+00:00"Gustavsson, Andreas"https://www.zbmath.org/authors/?q=ai:gustavsson.andreasSummary: We present a nonabelian Lagrangian that appears to have \((2, 0)\) superconformal symmetry and that can be coupled to a supergravity background. But for our construction to work, we have to break this superconformal symmetry by imposing as a constraint on top of the Lagrangian that the fields have vanishing Lie derivatives along a Killing direction.Effects of horizons on entanglement harvesting.https://www.zbmath.org/1456.830562021-04-16T16:22:00+00:00"Cong, Wan"https://www.zbmath.org/authors/?q=ai:cong.wan"Qian, Chen"https://www.zbmath.org/authors/?q=ai:qian.chen"Good, Michael R. R."https://www.zbmath.org/authors/?q=ai:good.michael-r-r"Mann, Robert B."https://www.zbmath.org/authors/?q=ai:mann.robert-bSummary: We study the effects of horizons on the entanglement harvested between two Unruh-DeWitt detectors via the use of moving mirrors with and without strict horizons. The entanglement reveals the sensitivity of the entanglement harvested to the global dynamics of the trajectories disclosing aspects of the effect that global information loss (where incoming massless scalar field modes from past null infinity cannot reach right future null infinity) has on local particle detectors. We also show that entanglement harvesting is insensitive to the sign of emitted radiation flux.Carroll versus Galilei from a brane perspective.https://www.zbmath.org/1456.830012021-04-16T16:22:00+00:00"Bergshoeff, Eric"https://www.zbmath.org/authors/?q=ai:bergshoeff.eric-a"Izquierdo, José Manuel"https://www.zbmath.org/authors/?q=ai:izquierdo.jose-manuel"Romano, Luca"https://www.zbmath.org/authors/?q=ai:romano.lucaSummary: We show that our previous work [\textit{E. Bergshoeff} et al., J. High Energy Phys. 2017, No. 3, Paper No. 165, 26 p. (2017; Zbl 1377.83073)] on Galilei and Carroll gravity, apt for particles, can be generalized to Galilei and Carroll gravity theories adapted to \(p\)-branes \((p = 0, 1, 2, \dots)\). Within this wider brane perspective, we make use of a formal map, given in the literature, between the corresponding \(p\)-brane Carroll and Galilei algebras where the index describing the directions longitudinal (transverse) to the Galilei brane is interchanged with the index covering the directions transverse (longitudinal) to the Carroll brane with the understanding that the time coordinate is always among the longitudinal directions. This leads among other things in 3D to a map between Galilei particles and Carroll strings and in 4D to a similar map between Galilei strings and Carroll strings. We show that this formal map extends to the corresponding Lie algebra expansion of the Poincaré algebra and, therefore, to several extensions of the Carroll and Galilei algebras including central extensions. We use this formal map to construct several new examples of Carroll gravity actions. Furthermore, we discuss the symmetry between Carroll and Galilei at the level of the \(p\)-brane sigma model action and apply this formal symmetry to give several examples of \(3D\) and \(4D\) particles and strings in a curved Carroll background.Making the case for causal dynamical triangulations.https://www.zbmath.org/1456.830182021-04-16T16:22:00+00:00"Cooperman, Joshua H."https://www.zbmath.org/authors/?q=ai:cooperman.joshua-hSummary: The aim of the causal dynamical triangulations approach is to define nonperturbatively a quantum theory of gravity as the continuum limit of a lattice-regularized model of dynamical geometry. My aim in this paper is to give a concise yet comprehensive, impartial yet personal presentation of the causal dynamical triangulations approach.Newtonian fractional-dimension gravity and MOND.https://www.zbmath.org/1456.830712021-04-16T16:22:00+00:00"Varieschi, Gabriele U."https://www.zbmath.org/authors/?q=ai:varieschi.gabriele-umbertoSummary: This paper introduces a possible alternative model of gravity based on the theory of fractional-dimension spaces and its applications to Newtonian gravity. In particular, Gauss's law for gravity as well as other fundamental classical laws are extended to a \(D\)-dimensional metric space, where \(D\) can be a non-integer dimension. We show a possible connection between this Newtonian Fractional-Dimension Gravity (NFDG) and Modified Newtonian Dynamics (MOND), a leading alternative gravity model which accounts for the observed properties of galaxies and other astrophysical structures without requiring the dark matter hypothesis. The MOND acceleration constant \({a_0} \simeq 1.2 \times 10^{-10} \text{m}\, \text{s}^{-2}\) can be related to a natural scale length \(l_0\) in NFDG, i.e., \(a_0 \approx GM/l_0^2\), for astrophysical structures of mass \(M\), and the deep-MOND regime is present in regions of space where the dimension is reduced to \(D \approx 2\). For several fundamental spherically-symmetric structures, we compare MOND results, such as the empirical Radial Acceleration Relation (RAR), circular speed plots, and logarithmic plots of the observed radial acceleration \(g_{obs}\) vs. the baryonic radial acceleration \(g_{bar}\), with NFDG results. We show that our model is capable of reproducing these results using a variable local dimension \(D\left( w\right)\), where \(w =r/l_0\) is a dimensionless radial coordinate. At the moment, we are unable to derive explicitly this dimension function \(D\left( w\right)\) from first principles, but it can be obtained empirically in each case from the general RAR. Additional work on the subject, including studies of axially-symmetric structures, detailed galactic rotation curves fitting, and a possible relativistic extension, will be needed to establish NFDG as a viable alternative model of gravity.Stringy canonical forms and binary geometries from associahedra, cyclohedra and generalized permutohedra.https://www.zbmath.org/1456.831012021-04-16T16:22:00+00:00"He, Song"https://www.zbmath.org/authors/?q=ai:he.song"Li, Zhenjie"https://www.zbmath.org/authors/?q=ai:li.zhenjie"Raman, Prashanth"https://www.zbmath.org/authors/?q=ai:raman.prashanth"Zhang, Chi"https://www.zbmath.org/authors/?q=ai:zhang.chiSummary: Stringy canonical forms are a class of integrals that provide \(\alpha\)'-deformations of the canonical form of any polytopes. For generalized associahedra of finite-type cluster algebras, there exist completely rigid stringy integrals, whose configuration spaces are the so-called binary geometries, and for classical types are associated with (generalized) scattering of particles and strings. In this paper, we propose a large class of rigid stringy canonical forms for another class of polytopes, generalized permutohedra, which also include associahedra and cyclohedra as special cases (type \(A_n\) and \(B_n\) generalized associahedra). Remarkably, we find that the configuration spaces of such integrals are also binary geometries, which were suspected to exist for generalized associahedra only. For any generalized permutohedron that can be written as Minkowski sum of coordinate simplices, we show that its rigid stringy integral factorizes into products of lower integrals for massless poles at finite \(\alpha\)', and the configuration space is binary although the \(u\) equations take a more general form than those ``perfect'' ones for cluster cases. Moreover, we provide an infinite class of examples obtained by degenerations of type \(A_n\) and \(B_n\) integrals, which have perfect \(u\) equations as well. Our results provide yet another family of generalizations of the usual string integral and moduli space, whose physical interpretations remain to be explored.The zeroth law of thermodynamics in special relativity.https://www.zbmath.org/1456.830042021-04-16T16:22:00+00:00"Gavassino, L."https://www.zbmath.org/authors/?q=ai:gavassino.lSummary: We critically revisit the definition of thermal equilibrium, in its operational formulation, provided by standard thermodynamics. We show that it refers to experimental conditions which break the covariance of the theory at a fundamental level and that, therefore, it cannot be applied to the case of moving bodies. We propose an extension of this definition which is manifestly covariant and can be applied to the study of isolated systems in special relativity. The zeroth law of thermodynamics is, then, proven to establish an equivalence relation among bodies which have not only the same temperature, but also the same center of mass four-velocity.Conformal invariance of the Newtonian Weyl tensor.https://www.zbmath.org/1456.830622021-04-16T16:22:00+00:00"Dewar, Neil"https://www.zbmath.org/authors/?q=ai:dewar.neil"Read, James"https://www.zbmath.org/authors/?q=ai:read.jamesSummary: It is well-known that the conformal structure of a relativistic spacetime is of profound physical and conceptual interest. In this note, we consider the analogous structure for Newtonian theories. We show that the Newtonian Weyl tensor is an invariant of this structure.Triple path to the exponential metric.https://www.zbmath.org/1456.830102021-04-16T16:22:00+00:00"Makukov, Maxim"https://www.zbmath.org/authors/?q=ai:makukov.maxim-a"Mychelkin, Eduard"https://www.zbmath.org/authors/?q=ai:mychelkin.eduard-gSummary: The exponential Papapetrou metric induced by scalar field conforms to observational data not worse than the vacuum Schwarzschild solution. Here, we analyze the origin of this metric as a peculiar space-time within a wide class of scalar and antiscalar solutions of the Einstein equations parameterized by scalar charge. Generalizing the three families of static solutions obtained by \textit{I. Z. Fisher} [``Scalar mesostatic field with regard for gravitational effects'', Zh. Èksper. Teor. Fiz. 18, 636--640 (1948), \url{https://cds.cern.ch/record/406391}], \textit{A. I. Janis} et al. [``Reality of the Schwarzschild singularity'', Phys. Rev. Lett. 20, No. 16, 878--880 (1968; \url{doi:10.1103/PhysRevLett.20.878})], and \textit{B. C. Xanthopoulos} and \textit{T. Zannias} [``Einstein gravity coupled to a massless scalar field in arbitrary spacetime dimensions'', Phys. Rev. D (3) 40, No. 8, 2564--2567 (1989; \url{doi:10.1103/PhysRevD.40.2564})], we prove that all three reduce to the same exponential metric provided that scalar charge is equal to central mass, thereby suggesting the universal character of such background scalar field.On the equivalence principle and relativistic quantum mechanics.https://www.zbmath.org/1456.830082021-04-16T16:22:00+00:00"Trzetrzelewski, Maciej"https://www.zbmath.org/authors/?q=ai:trzetrzelewski.maciejSummary: Einstein's Equivalence Principle implies that the Lorentz force equation can be derived from a geodesic equation by imposing a certain (necessary) condition on the electromagnetic potential [the author, ``On the equivalence principle and electrodynamics of moving bodies'', Preprint, \url{arXiv:1503.05577}]. We analyze the quantization of that constraint and find the corresponding differential equations for the phase of the wave function. We investigate these equations in the case of Coulomb potential and show that physically acceptable solutions do not exist. This result signals an inconsistency between Einstein's Equivalence Principle and Relativistic Quantum Mechanics at an atomic level.Addressing the cosmological \(H_0\) tension by the Heisenberg uncertainty.https://www.zbmath.org/1456.831192021-04-16T16:22:00+00:00"Capozziello, Salvatore"https://www.zbmath.org/authors/?q=ai:capozziello.salvatore"Benetti, Micol"https://www.zbmath.org/authors/?q=ai:benetti.micol"Spallicci, Alessandro D. A. M."https://www.zbmath.org/authors/?q=ai:spallicci.alessandro-d-a-mSummary: The uncertainty on measurements, given by the Heisenberg principle, is a quantum concept usually not taken into account in General Relativity. From a cosmological point of view, several authors wonder how such a principle can be reconciled with the Big Bang singularity, but, generally, not whether it may affect the reliability of cosmological measurements. In this letter, we express the Compton mass as a function of the cosmological redshift. The cosmological application of the indetermination principle unveils the differences of the Hubble-Lemaître constant value, \(H_0\), as measured from the Cepheids estimates and from the Cosmic Microwave Background radiation constraints. In conclusion, the \(H_0\) tension could be related to the effect of indetermination derived in comparing a kinematic with a dynamic measurement.Petz reconstruction in random tensor networks.https://www.zbmath.org/1456.813422021-04-16T16:22:00+00:00"Jia, Hewei Frederic"https://www.zbmath.org/authors/?q=ai:jia.hewei-frederic"Rangamani, Mukund"https://www.zbmath.org/authors/?q=ai:rangamani.mukundSummary: We illustrate the ideas of bulk reconstruction in the context of random tensor network toy models of holography. Specifically, we demonstrate how the Petz [\textit{D. Petz}, Commun. Math. Phys. 105, 123--131 (1986; Zbl 0597.46067)] reconstruction map works to obtain bulk operators from the boundary data by exploiting the replica trick. We also take the opportunity to comment on the differences between coarse-graining and random projections.On TCS \(G_2\) manifolds and 4D emergent strings.https://www.zbmath.org/1456.831092021-04-16T16:22:00+00:00"Xu, Fengjun"https://www.zbmath.org/authors/?q=ai:xu.fengjunSummary: In this note, we study the Swampland Distance Conjecture in TCS \(G_2\) manifold compactifications of M-theory. In particular, we are interested in testing a refined version --- the Emergent String Conjecture, in settings with 4d \(N = 1\) supersymmetry. We find that a weakly coupled, tensionless fundamental heterotic string does emerge at the infinite distance limit characterized by shrinking the \(K3\)-fiber in a TCS \(G_2\) manifold. Such a fundamental tensionless string leads to the parametrically leading infinite tower of asymptotically massless states, which is in line with the Emergent String Conjecture. The tensionless string, however, receives quantum corrections. We check that these quantum corrections do modify the volume of the shrinking \(K3\)-fiber via string duality and hence make the string regain a non-vanishing tension at the quantum level, leading to a decompactification. Geometrically, the quantum corrections modify the metric of the classical moduli space and are expected to obstruct the infinite distance limit. We also comment on another possible type of infinite distance limit in TCS \(G_2\) compactifications, which might lead to a weakly coupled fundamental type II string theory.Establishing strongly-coupled 3D AdS quantum gravity with Ising dual using all-genus partition functions.https://www.zbmath.org/1456.830262021-04-16T16:22:00+00:00"Jian, Chao-Ming"https://www.zbmath.org/authors/?q=ai:jian.chao-ming"Ludwig, Andreas W. W."https://www.zbmath.org/authors/?q=ai:ludwig.andreas-w-w"Luo, Zhu-Xi"https://www.zbmath.org/authors/?q=ai:luo.zhu-xi"Sun, Hao-Yu"https://www.zbmath.org/authors/?q=ai:sun.hao-yu"Wang, Zhenghan"https://www.zbmath.org/authors/?q=ai:wang.zhenghanSummary: We study 3D pure Einstein quantum gravity with negative cosmological constant, in the regime where the AdS radius \(l\) is of the order of the Planck scale. Specifically, when the Brown-Henneaux central charge \(c = 3 l/ 2G_N\), (\(G_N\) is the 3D Newton constant) equals \(c = 1/2\), we establish duality between 3D gravity and 2D Ising conformal field theory by matching gravity and conformal field theory partition functions for AdS spacetimes with general asymptotic boundaries. This duality was suggested by a genus-one calculation of \textit{A. Castro} et al. [``Gravity dual of the Ising model'', Phys. Rev. D 85, No. 2, Article ID 024032, 22 p. (2012; \url{doi:10.1103/PhysRevD.85.024032})]. Extension beyond genus-one requires new mathematical results based on 3D Topological Quantum Field Theory; these turn out to uniquely select the \(c = 1/2\) theory among all those with \textit{c <} 1, extending the previous results of Castro et al. Previous work suggests the reduction of the calculation of the gravity partition function to a problem of summation over the orbits of the mapping class group action on a ``vacuum seed''. But whether or not the summation is well-defined for the general case was unknown before this work. Amongst all theories with Brown-Henneaux central charge \(c < 1\), the sum is finite and unique \textit{only} when \(c = 1/2\), corresponding to a dual Ising conformal field theory on the asymptotic boundary.Distributions of extremal black holes in Calabi-Yau compactifications.https://www.zbmath.org/1456.830422021-04-16T16:22:00+00:00"Hulsey, George"https://www.zbmath.org/authors/?q=ai:hulsey.george"Kachru, Shamit"https://www.zbmath.org/authors/?q=ai:kachru.shamit"Yang, Sungyeon"https://www.zbmath.org/authors/?q=ai:yang.sungyeon"Zimet, Max"https://www.zbmath.org/authors/?q=ai:zimet.maxSummary: We study non-supersymmetric extremal black hole excitations of 4d \(\mathcal{N} = 2\) supersymmetric string vacua arising from compactification on Calabi-Yau threefolds. The values of the (vector multiplet) moduli at the black hole horizon are governed by the attractor mechanism. This raises natural questions, such as ``what is the distribution of attractor points on moduli space?'' and ``how many attractor black holes are there with horizon area up to a certain size?'' We employ tools developed by \textit{F. Denef} and \textit{M. R. Douglas} [``Distributions of flux vacua'', J. High Energy Phys. 2004, No. 5, Paper No. 072, 46 p. (2004; \url{doi:10.1088/1126-6708/2004/05/072})] to answer these questions.A cubic deformation of ABJM: the squashed, stretched, warped, and perturbed gets invaded.https://www.zbmath.org/1456.831132021-04-16T16:22:00+00:00"Cesàro, Mattia"https://www.zbmath.org/authors/?q=ai:cesaro.mattia"Larios, Gabriel"https://www.zbmath.org/authors/?q=ai:larios.gabriel"Varela, Oscar"https://www.zbmath.org/authors/?q=ai:varela.oscarSummary: A superpotential deformation that is cubic in one of the chiral superfields of ABJM makes the latter theory flow into a new \(\mathcal{N} = 2\) superconformal phase. This is holographically dual to a warped \(\mathrm{ AdS}_4 \times_w S^7\) solution of M-theory equipped with a squashed and stretched metric on \(S^7\). We determine the spectrum of spin-2 operators of the cubic deformation at low energies by computing the spectrum of Kaluza-Klein (KK) gravitons over the dual \(\mathrm{AdS}_4\) solution. We calculate, numerically, the complete graviton spectrum and, analytically, the spectrum of gravitons that belong to short multiplets. We also use group theory to assess the structure of the full KK spectrum, and conclude that \(\mathcal{N} = 2\) supermultiplets cannot be allocated KK level by KK level. This phenomenon, usually referred to as ``space invaders scenario'', is also known to occur for another \(\mathrm{AdS}_4\) solution based on a different squashed \(S^7\).Topological field theories of 2- and 3-forms in six dimensions.https://www.zbmath.org/1456.814072021-04-16T16:22:00+00:00"Herfray, Yannick"https://www.zbmath.org/authors/?q=ai:herfray.yannick"Krasnov, Kirill"https://www.zbmath.org/authors/?q=ai:krasnov.kirill-vSummary: We consider several diffeomorphism invariant field theories of 2- and 3-forms in six dimensions. They all share the same kinetic term \(BdC\) but differ in the potential term that is added. The theory \(BdC\) with no potential term is topological -- it describes no propagating degrees of freedom. We show that the theory continues to remain topological when either the \(BBB\) or \(C \hat{C}\) potential term is added. The latter theory can be viewed as a background independent version of the 6-dimensional Hitchin theory, for its critical points are complex or para-complex 6-manifolds, but unlike in Hitchin's construction, one does not need to choose a background cohomology class to define the theory. We also show that the dimensional reduction of the \(C \hat{C}\) theory to three dimensions, when reducing on \(S^{3}\), gives 3D gravity.{
\copyright 2017 American Institute of Physics}A \(U(1)_{B- L}\)-extension of the standard model from noncommutative geometry.https://www.zbmath.org/1456.814712021-04-16T16:22:00+00:00"Besnard, Fabien"https://www.zbmath.org/authors/?q=ai:besnard.fabienSummary: We derive a \(U(1)_{B- L}\)-extension of the standard model from a generalized Connes-Lott model with algebra \(\mathbb{C} \oplus \mathbb{C} \oplus \mathbb{H} \oplus M_3(\mathbb{C})\). This generalization includes the Lorentzian signature, the presence of a real structure, and the weakening of the order 1 condition. In addition to the SM fields, it contains a \(Z_{B- L}\)' boson and a complex scalar field \(\sigma\) that spontaneously breaks the new symmetry. This model is the smallest one that contains the SM fields and is compatible with both the Connes-Lott theory and the algebraic background framework.
{\copyright 2021 American Institute of Physics}Out of the swampland with multifield quintessence?https://www.zbmath.org/1456.831202021-04-16T16:22:00+00:00"Cicoli, Michele"https://www.zbmath.org/authors/?q=ai:cicoli.michele"Dibitetto, Giuseppe"https://www.zbmath.org/authors/?q=ai:dibitetto.giuseppe"Pedro, Francisco G."https://www.zbmath.org/authors/?q=ai:pedro.francisco-gSummary: Multifield models with a curved field space have already been shown to be able to provide viable quintessence models for steep potentials that satisfy swampland bounds. The simplest dynamical systems of this type are obtained by coupling Einstein gravity to two scalar fields with a curved field space. In this paper we study the stability properties of the non-trivial fixed points of this dynamical system for a general functional dependence of the kinetic coupling function and the scalar potential. We find the existence of non-geodesic trajectories with a sharp turning rate in field space which can give rise to late-time cosmic acceleration with no need for flat potentials. In particular, we discuss the properties of the phase diagram of the system and the corresponding time evolution when varying the functional dependence of the kinetic coupling. Interestingly, upon properly tuning the initial conditions of the field values, we find trajectories that can describe the current state of the universe. This could represent a promising avenue to build viable quintessence models out of the swampland if they could be consistently embedded in explicit string constructions.Microstate geometries from gauged supergravity in three dimensions.https://www.zbmath.org/1456.831152021-04-16T16:22:00+00:00"Mayerson, Daniel R."https://www.zbmath.org/authors/?q=ai:mayerson.daniel-r"Walker, Robert A."https://www.zbmath.org/authors/?q=ai:walker.robert-a|walker.robert-a-ii"Warner, Nicholas P."https://www.zbmath.org/authors/?q=ai:warner.nicholas-pSummary: The most detailed constructions of microstate geometries, and particularly of superstrata, are done using \(\mathcal{N} = (1, 0)\) supergravity coupled to two anti-self-dual tensor multiplets in six dimensions. We show that an important sub-sector of this theory has a consistent truncation to a particular gauged supergravity in three dimensions. Our consistent truncation is closely related to those recently laid out by Samtleben and Sarıoğlu, which enables us to develop complete uplift formulae from the three-dimensional theory to six dimensions. We also find a new family of multi-mode superstrata, indexed by two arbitrary holomorphic functions of one complex variable, that live within our consistent truncation and use this family to provide extensive tests of our consistent truncation. We discuss some of the future applications of having an intrinsically three-dimensional formulation of a significant class of microstate geometries.Horizon radiation reaction forces.https://www.zbmath.org/1456.830332021-04-16T16:22:00+00:00"Goldberger, Walter D."https://www.zbmath.org/authors/?q=ai:goldberger.walter-d"Rothstein, Ira Z."https://www.zbmath.org/authors/?q=ai:rothstein.ira-zSummary: Using Effective Field Theory (EFT) methods, we compute the effects of horizon dissipation on the gravitational interactions of relativistic binary black hole systems. We assume that the dynamics is perturbative, i.e it admits an expansion in powers of Newton's constant (post-Minkowskian, or PM, approximation). As applications, we compute corrections to the scattering angle in a black hole collision due to dissipative effects to leading PM order, as well as the post-Newtonian (PN) corrections to the equations of motion of binary black holes in non-relativistic orbits, which represents the leading order finite size effect in the equations of motion. The methods developed here are also applicable to the case of more general compact objects, eg. neutron stars, where the magnitude of the dissipative effects depends on non-gravitational physics (e.g, the equation of state for nuclear matter).The constraint equations in the presence of a scalar field: the case of the conformal method with volumetric drift.https://www.zbmath.org/1456.530552021-04-16T16:22:00+00:00"Vâlcu, Caterina"https://www.zbmath.org/authors/?q=ai:valcu.caterinaThe author applies the conformal method to determine the classical system of constraint equations and certain conditions are imposed on the presence of matter field. A priori estimates for solutions of the Lichnerowicz equation are also discussed. The conformal systems established by Maxwell in the presence of a scalar field and appropriate parameters are established.
Further, in closed Riemannian manifolds of dimension 3, 4 and 5, metrics with and without conformal Killing fields are considered and some important results are established.
Reviewer: Mohammad Nazrul Islam Khan (Buraidah)Electromagnetic quasitopological gravities.https://www.zbmath.org/1456.830612021-04-16T16:22:00+00:00"Cano, Pablo A."https://www.zbmath.org/authors/?q=ai:cano.pablo-a"Murcia, Ángel"https://www.zbmath.org/authors/?q=ai:murcia.angelSummary: We identify a set of higher-derivative extensions of Einstein-Maxwell theory that allow for spherically symmetric charged solutions characterized by a single metric function \(f (r) = - g_{ tt } = 1/g_{ rr }\). These theories are a non-minimally coupled version of the recently constructed Generalized Quasitopological gravities and they satisfy a number of properties that we establish. We study magnetically-charged black hole solutions in these new theories and we find that for some of them the equations of motion can be fully integrated, enabling us to obtain analytic solutions. In those cases we show that, quite generally, the singularity at the core of the black hole is removed by the higher-derivative corrections and that the solution describes a globally regular geometry. In other cases, the equations are reduced to a second order equation for \(f (r)\). Nevertheless, for all the theories it is possible to study the thermodynamic properties of charged black holes analytically. We show that the first law of thermodynamics holds exactly and that the Euclidean and Noether-charge methods provide equivalent results. We then study extremal black holes, focusing on the corrections to the extremal charge-to-mass ratio at a non-perturbative level. We observe that in some theories there are no extremal black holes below certain mass. We also show the existence of theories for which extremal black holes do not represent the minimal mass state for a given charge. The implications of these findings for the evaporation process of black holes are discussed.Exact results and Schur expansions in quiver Chern-Simons-matter theories.https://www.zbmath.org/1456.814422021-04-16T16:22:00+00:00"Santilli, Leonardo"https://www.zbmath.org/authors/?q=ai:santilli.leonardo"Tierz, Miguel"https://www.zbmath.org/authors/?q=ai:tierz.miguelSummary: We study several quiver Chern-Simons-matter theories on the three-sphere, combining the matrix model formulation with a systematic use of Mordell's integral, computing partition functions and checking dualities. We also consider Wilson loops in ABJ(M) theories, distinguishing between typical (long) and atypical (short) representations and focusing on the former. Using the Berele-Regev factorization of supersymmetric Schur polynomials, we express the expectation value of the Wilson loops in terms of sums of observables of two factorized copies of \(\mathrm{U}(N\)) pure Chern-Simons theory on the sphere. Then, we use the Cauchy identity to study the partition functions of a number of quiver Chern-Simons-matter models and the result is interpreted as a perturbative expansion in the parameters \(t_j = - e^{2 \pi m_j }\), where \(m_j\) are the masses. Through the paper, we incorporate different generalizations, such as deformations by real masses and/or Fayet-Iliopoulos parameters, the consideration of a Romans mass in the gravity dual, and adjoint matter.Inscribed radius bounds for lower Ricci bounded metric measure spaces with mean convex boundary.https://www.zbmath.org/1456.510072021-04-16T16:22:00+00:00"Burtscher, Annegret"https://www.zbmath.org/authors/?q=ai:burtscher.annegret-y"Ketterer, Christian"https://www.zbmath.org/authors/?q=ai:ketterer.christian"McCann, Robert J."https://www.zbmath.org/authors/?q=ai:mccann.robert-j"Woolgar, Eric"https://www.zbmath.org/authors/?q=ai:woolgar.eric\textit{A. Kasue} [J. Math. Soc. Japan 35, 117--131 (1983; Zbl 0494.53039)] established a sharp estimate for the inscribed radius,
or inradius denoted \(\mathrm{InRad}\), of a smooth \(n\)-dimensional Riemannian manifold \(M\) with nonnegative Ricci curvature and smooth boundary \(\partial M\)\ whose mean curvature is bounded from below by \(n-1\). Exactly speaking, he concluded that
\[
\mathrm{InRad}_{M}\leq 1.
\]
The result was rediscovered by [\textit{M. M. C. Li}, J. Geom. Anal. 24, No. 3, 1490--1496 (2014; Zbl 1303.53053)], being extended to weighted Riemannian manifolds with Bakry-Émery curvature bounds in [\textit{H. Li} and \textit{Y. Wei}, J. Geom. Anal. 25, No. 1, 421--435 (2015; Zbl 1320.53075); Int. Math. Res. Not. 2015, No. 11, 3651--3668 (2015; Zbl 1317.53065); \textit{Y. Sakurai}, Tohoku Math. J. (2) 71, No. 1, 69--109 (2019; Zbl 1422.53029)]. These results are to be seen either as a manifold-with-boundary analogue of Bonnet and Myers' diameter bound or as a Riemannian analogue of the Hawking singularity theorem [\textit{S. W. Hawking}, Proc. R. Soc. Lond., Ser. A 294, 511--521 (1966; Zbl 0139.45803)], whose generalization to a nonsmooth setting is of paramount interest [\textit{M. Graf}, Commun. Math. Phys. 378, No. 2, 1417--1450 (2020; Zbl 1445.53052); \textit{M. Kunzinger} et al., Classical Quantum Gravity 32, No. 7, Article ID 075012, 19 p. (2015; Zbl 1328.83123); \textit{Y. Lu} et al., ``Geometry of weighted Lorentz-Finsler manifolds. I: Singularity theorems'', Preprint, \url{arXiv:1908.03832}].
This paper generalizes Kasue's [loc. cit.] and Li's [loc. cit.] estimate to subsets \(\Omega\)\ of a possibly nonsmooth space \(X\) abiding by a curvature dimension condition \(\mathrm{CD}(K,N)\) with \(K\in\mathbb{R}\) and \(N>1\), provided the topological boundary \(\partial\Omega\) has a lower bound on its inner mean curvature in the sense of [\textit{C. Ketterer}, Proc. Am. Math. Soc. 148, No. 9, 4041--4056 (2020; Zbl 1444.53028)]. The authors' result not only covers Kasue's [loc. cit.] theorem but also holds for a large class of domains in Alexandrov spaces or in Finsler manifolds. Kasue [loc. cit.] as well as Li [loc. cit.] was able to establish a rigidity result analogous to \textit{S.-Y. Cheng}'s theorem [Math. Z. 143, 289--297 (1975; Zbl 0329.53035)] in the Bonnet-Myers context [\textit{S. B. Myers}, Duke Math. J. 8, 401--404 (1941; JFM 67.0673.01); \textit{S. B. Myers}, Duke Math. J. 8, 401--404 (1941; Zbl 0025.22704)], namely that, among smooth manifolds, their inscribed radious bound is obtained exactly by the Euclidean unit ball. In the nonsmooth case, there are also truncated cones attaining maximal inradius. The authors establish, under an additional hypothesis known as RCD, that these are the only nonsmooth oprimizers provided \(\Omega\)\ is compact and its interior is connected.
Independently and almost simultaneously, \textit{F. Cavalletti} and \textit{A. Mondino} [Commun. Contemp. Math. 19, No. 6, Article ID 1750007, 27 p. (2017; Zbl 1376.53064); Invent. Math. 208, No. 3, 803--849 (2017; Zbl 1375.53053); Anal. PDE 13, 2091--2147 (2020); ``Optimal transport in Lorentzian synthetic spaces, synthetic timelike Ricci curvature lower bounds and applications'', Preprint, \url{arXiv:2004.08934}] have proposed a synthetic new framework for Lorentzian
geometry in which an analogue of the Hawking result is established.
Reviewer: Hirokazu Nishimura (Tsukuba)Thin-shell wormholes in \(\mathrm{AdS}_5\) and string dioptrics.https://www.zbmath.org/1456.830922021-04-16T16:22:00+00:00"Chernicoff, Mariano"https://www.zbmath.org/authors/?q=ai:chernicoff.mariano"García, Edel"https://www.zbmath.org/authors/?q=ai:garcia.edel-b"Giribet, Gaston"https://www.zbmath.org/authors/?q=ai:giribet.gaston-e"de Celis, Emilio Rubín"https://www.zbmath.org/authors/?q=ai:de-celis.emilio-rubinSummary: We consider string probes in a traversable wormhole geometry that connects two locally \(\mathrm{ AdS}_5\) asymptotic regions. Holographically, this describes two interacting copies of a 4-dimensional gauge theory. We consider string configurations whose endpoints are located either in the same boundary or in the two different boundaries of the wormhole. A string with both endpoints in the same boundary is dual to a quark-antiquark pair charged under the same gauge field, while a string extending through the wormhole describes a pair of colored particles charged under two different gauge fields. When one considers a quark-antiquark pair in each boundary, the system undergoes a phase transition: while for small separation each pair of charges exhibits Coulomb interaction, for large separation the charges in different field theories pair up. This behavior had previously been observed in other geometric realizations such as locally \(\mathrm{AdS}_5\) wormhole solutions with hyperbolic throats. The geometries we consider here, in contrast, are stable thin-shell wormholes with flat codimension-one hypersurfaces at fixed radial coordinate. They appear as electrovacuum solutions of higher-curvature gravity theories coupled to abelian gauge fields. The presence of the thin-shells produces a refraction of the string configurations in the bulk, leading to the presence of cusps in the phase space diagram. We discuss these and other features of the phase diagram, including the analogies and difference with other wormhole solutions considered in related contexts.4-dimensional manifolds with nonnegative scalar curvature and CMC boundary.https://www.zbmath.org/1456.530332021-04-16T16:22:00+00:00"Wang, Yaohua"https://www.zbmath.org/authors/?q=ai:wang.yaohuaMetric algebroid and Dirac generating operator in Double Field Theory.https://www.zbmath.org/1456.830902021-04-16T16:22:00+00:00"Carow-Watamura, Ursula"https://www.zbmath.org/authors/?q=ai:carow-watamura.ursula"Miura, Kohei"https://www.zbmath.org/authors/?q=ai:miura.kohei"Watamura, Satoshi"https://www.zbmath.org/authors/?q=ai:watamura.satoshi"Yano, Taro"https://www.zbmath.org/authors/?q=ai:yano.taroSummary: We give a formulation of Double Field Theory (DFT) based on a metric algebroid. We derive a covariant completion of the Bianchi identities, i.e. the pre-Bianchi identity in torsion and an improved generalized curvature, and the pre-Bianchi identity including the dilaton contribution. The derived bracket formulation by the Dirac generating operator is applied to the metric algebroid. We propose a generalized Lichnerowicz formula and show that it is equivalent to the pre-Bianchi identities. The dilaton in this setting is included as an ambiguity in the divergence. The projected generalized Lichnerowicz formula gives a new formulation of the DFT action. The closure of the generalized Lie derivative on the spin bundle yields the Bianchi identities as a consistency condition. A relation to the generalized supergravity equations (GSE) is discussed.Moduli stabilisation and the statistics of SUSY breaking in the landscape.https://www.zbmath.org/1456.831112021-04-16T16:22:00+00:00"Broeckel, Igor"https://www.zbmath.org/authors/?q=ai:broeckel.igor"Cicoli, Michele"https://www.zbmath.org/authors/?q=ai:cicoli.michele"Maharana, Anshuman"https://www.zbmath.org/authors/?q=ai:maharana.anshuman"Singh, Kajal"https://www.zbmath.org/authors/?q=ai:singh.kajal"Sinha, Kuver"https://www.zbmath.org/authors/?q=ai:sinha.kuverSummary: The statistics of the supersymmetry breaking scale in the string landscape has been extensively studied in the past finding either a power-law behaviour induced by uniform distributions of F-terms or a logarithmic distribution motivated by dynamical supersymmetry breaking. These studies focused mainly on type IIB flux compactifications but did not systematically incorporate the Kähler moduli. In this paper we point out that the inclusion of the Kähler moduli is crucial to understand the distribution of the supersymmetry breaking scale in the landscape since in general one obtains unstable vacua when the F-terms of the dilaton and the complex structure moduli are larger than the F- terms of the Kähler moduli. After taking Kähler moduli stabilisation into account, we find that the distribution of the gravitino mass and the soft terms is power-law only in KKLT and perturbatively stabilised vacua which therefore favour high scale supersymmetry. On the other hand, LVS vacua feature a logarithmic distribution of soft terms and thus a preference for lower scales of supersymmetry breaking. Whether the landscape of type IIB flux vacua predicts a logarithmic or power-law distribution of the supersymmetry breaking scale thus depends on the relative preponderance of LVS and KKLT vacua.Multi-Regge limit of the two-loop five-point amplitudes in \(\mathcal{N} = 4\) super Yang-Mills and \(\mathcal{N} = 8\) supergravity.https://www.zbmath.org/1456.831122021-04-16T16:22:00+00:00"Caron-Huot, Simon"https://www.zbmath.org/authors/?q=ai:caron-huot.simon"Chicherin, Dmitry"https://www.zbmath.org/authors/?q=ai:chicherin.dmitry"Henn, Johannes"https://www.zbmath.org/authors/?q=ai:henn.johannes-m"Zhang, Yang"https://www.zbmath.org/authors/?q=ai:zhang.yang"Zoia, Simone"https://www.zbmath.org/authors/?q=ai:zoia.simoneSummary: In previous work [\textit{E. D'Hoker} et al.,ibid. 2020, No. 8, Paper No. 135, 80 p. (2020; Zbl 1454.83159); \textit{C. R. Mafra} and \textit{O. Schlotterer}, ibid. 2015, No. 10, Paper No. 124, 29 p. (2015; Zbl 1388.83860)], the two-loop five-point amplitudes in \(\mathcal{N} = 4\) super Yang-Mills theory and \(\mathcal{N} = 8\) supergravity were computed at symbol level. In this paper, we compute the full functional form. The amplitudes are assembled and simplified using the analytic expressions of the two-loop pentagon integrals in the physical scattering region. We provide the explicit functional expressions, and a numerical reference point in the scattering region. We then calculate the multi-Regge limit of both amplitudes. The result is written in terms of an explicit transcendental function basis. For certain non-planar colour structures of the \(\mathcal{N} = 4\) super Yang-Mills amplitude, we perform an independent calculation based on the BFKL effective theory. We find perfect agreement. We comment on the analytic properties of the amplitudes.On the Vilkovisky-DeWitt approach and renormalization group in effective quantum gravity.https://www.zbmath.org/1456.830252021-04-16T16:22:00+00:00"Giacchini, Breno L."https://www.zbmath.org/authors/?q=ai:giacchini.breno-loureiro"de Paula Netto, Tibério"https://www.zbmath.org/authors/?q=ai:de-paula-netto.tiberio"Shapiro, Ilya L."https://www.zbmath.org/authors/?q=ai:shapiro.ilya-lSummary: The effective action in quantum general relativity is strongly dependent on the gauge-fixing and parametrization of the quantum metric. As a consequence, in the effective approach to quantum gravity, there is no possibility to introduce the renormalization-group framework in a consistent way. On the other hand, the version of effective action proposed by Vilkovisky and DeWitt does not depend on the gauge-fixing and parametrization off- shell, opening the way to explore the running of the cosmological and Newton constants as well as the coefficients of the higher-derivative terms of the total action. We argue that in the effective framework the one-loop beta functions for the zero-, two- and four-derivative terms can be regarded as exact, that means, free from corrections coming from the higher loops. In this perspective, the running describes the renormalization group flow between the present-day Hubble scale in the IR and the Planck scale in the UV.The non-SUSY \(\mathrm{AdS}_6\) and \(\mathrm{AdS}_7\) fixed points are brane-jet unstable.https://www.zbmath.org/1456.831182021-04-16T16:22:00+00:00"Suh, Minwoo"https://www.zbmath.org/authors/?q=ai:suh.minwooSummary: In six- and seven-dimensional gauged supergravity, each scalar potential has one supersymmetric and one non-supersymmetric fixed points. The non-supersymmetric \(\mathrm{AdS}_7\) fixed point is perturbatively unstable. On the other hand, the non-supersymmetric \(\mathrm{AdS}_6\) fixed point is known to be perturbatively stable. In this note we examine the newly proposed non-perturbative decay channel, called brane-jet instabilities of the \(\mathrm{ AdS}_6\) and \(\mathrm{AdS}_7\) vacua. We find that when they are uplifted to massive type IIA and eleven-dimensional supergravity, respectively, the non-supersymmetric \(\mathrm{AdS}_6\) and \(\mathrm{AdS}_7\) vacua are both brane-jet unstable, in fond of the weak gravity conjecture.Regge OPE blocks and light-ray operators.https://www.zbmath.org/1456.812582021-04-16T16:22:00+00:00"Kobayashi, Nozomu"https://www.zbmath.org/authors/?q=ai:kobayashi.nozomu"Nishioka, Tatsuma"https://www.zbmath.org/authors/?q=ai:nishioka.tatsuma"Okuyama, Yoshitaka"https://www.zbmath.org/authors/?q=ai:okuyama.yoshitakaSummary: We consider the structure of the operator product expansion (OPE) in conformal field theory by employing the OPE block formalism. The OPE block acted on the vacuum is promoted to an operator and its implications are examined on a non-vacuum state. We demonstrate that the OPE block is dominated by a light-ray operator in the Regge limit, which reproduces precisely the Regge behavior of conformal blocks when used inside scalar four-point functions. Motivated by this observation, we propose a new form of the OPE block, called the light-ray channel OPE block that has a well-behaved expansion dominated by a light-ray operator in the Regge limit. We also show that the two OPE blocks have the same asymptotic form in the Regge limit and confirm the assertion that the Regge limit of a pair of spacelike-separated operators in a Minkowski patch is equivalent to the OPE limit of a pair of timelike-separated operators associated with the original pair in a different Minkowski patch.Bootstrapping conformal four-point correlators with slightly broken higher spin symmetry and \(3D\) bosonization.https://www.zbmath.org/1456.830832021-04-16T16:22:00+00:00"Li, Zhijin"https://www.zbmath.org/authors/?q=ai:li.zhijinSummary: Three-dimensional conformal field theories (CFTs) with slightly broken higher spin symmetry provide an interesting laboratory to study general properties of CFTs and their roles in the AdS/CFT correspondence. In this work we compute the planar four-point functions at arbitrary 't Hooft coupling \(\lambda\) in the CFTs with slightly broken higher spin symmetry. We use a bootstrap approach based on the approximate higher spin Ward identity. We show that the bootstrap equation is separated into two parts with opposite parity charges, and it leads to a recursion relation for the \(\lambda\) expansions of the correlation functions. The \(\lambda\) expansions terminate at order \(\lambda^2\) and the solutions are exact in \(\lambda\). Our work generalizes the approach proposed by Maldacena and Zhiboedov to four-point correlators, and it amounts to an on-shell study for the \(3D\) Chern-Simons vector models and their holographic duals in \(\mathrm{AdS}_4\). Besides, we show that the same results can also be obtained rather simply from bosonization duality of \(3D\) Chern-Simons vector models. The odd term at order \(O( \lambda)\) in the spinning four-point function relates to the free boson correlator through a Legendre transformation. This provides new evidence on the \(3D\) bosonization duality at the spinning four-point function level. We expect this work can be generalized to a complete classification of general four-point functions of single trace currents.Size of bulk fermions in the SYK model.https://www.zbmath.org/1456.830592021-04-16T16:22:00+00:00"Lensky, Yuri D."https://www.zbmath.org/authors/?q=ai:lensky.yuri-d"Qi, Xiao-Liang"https://www.zbmath.org/authors/?q=ai:qi.xiao-liang"Zhang, Pengfei"https://www.zbmath.org/authors/?q=ai:zhang.pengfeiSummary: The study of quantum gravity in the form of the holographic duality has uncovered and motivated the detailed investigation of various diagnostics of quantum chaos. One such measure is the operator size distribution, which characterizes the size of the support region of an operator and its evolution under Heisenberg evolution. In this work, we examine the role of the operator size distribution in holographic duality for the Sachdev-Ye-Kitaev (SYK) model. Using an explicit construction of \(\mathrm{AdS}_2\) bulk fermion operators in a putative dual of the low temperature SYK model, we study the operator size distribution of the boundary and bulk fermions. Our result provides a direct derivation of the relationship between (effective) operator size of both the boundary and bulk fermions and bulk \(\mathrm{SL} (2; \mathbb{R})\) generators.Semi-classical limit of quantum free energy minimizers for the gravitational Hartree equation.https://www.zbmath.org/1456.811882021-04-16T16:22:00+00:00"Choi, Woocheol"https://www.zbmath.org/authors/?q=ai:choi.woocheol"Hong, Younghun"https://www.zbmath.org/authors/?q=ai:hong.younghun"Seok, Jinmyoung"https://www.zbmath.org/authors/?q=ai:seok.jinmyoungThe authors consider the gravitational Vlasov-Poisson equation for a plasma in a gravitational field. They assume that their approach would be valid for large complexes of stars like white dwarfs with a number of stars $N>10^8$ or $N>10^{14}$ for giant stars. The main idea of the actual article is as follows. There is a number of research in which one construct free energy minimizers under some mass constrains.
From an another hand there are also researches which investigate free energy minimizers for the quantum problem, based on the well known Hartree-Fock mean field method.
The problem which is solved by the authors of the actual article concerns with the correspondence between quantum and classical isotropic states. The authors prove some theorems stating that in the limit of very small quantum Planck constant ( when the Planck constant is going to 0), the free energy minimizers for the Hartree-Fock equation converge to those for the Vlasov-Poisson equation in terms of potential functions, as well as via the Wigner transform and the Toplitz quantization.
The authors mention throughout the text of the article an earlier research (1961, 1962) by V.A. Antonov, which is proving the stability of the Vlasov-Poisson equation, applied for stellar many-bodies systems with large number of components. Let us mention, that the famous paper by A.A. Vlasov which established a new kinetic equation for plasma was published in 1938 and only much later was recognized as a correct equation for plasma. See, about this the book by \textit{I. P. Bazarov}, and \textit{P. N. Nikolaev} [Anatolij Aleksandrovich Vlasov ( in Russian), 2nd edition, 63 p. (1999; \url{http:// phys.msu.ru/upload/iblock/0cc/ vlasov-book.pdf})].
Reviewer: Alex B. Gaina (Chisinau)Chaos from massive deformations of Yang-Mills matrix models.https://www.zbmath.org/1456.813302021-04-16T16:22:00+00:00"Başkan, K."https://www.zbmath.org/authors/?q=ai:baskan.k"Kürkçüoğlu, S."https://www.zbmath.org/authors/?q=ai:kurkcuoglu.seckin-kin"Oktay, O."https://www.zbmath.org/authors/?q=ai:oktay.onur"Taşcı, C."https://www.zbmath.org/authors/?q=ai:tasci.cSummary: We focus on an \(\mathrm{SU} (N)\) Yang-Mills gauge theory in 0 + 1-dimensions with the same matrix content as the bosonic part of the BFSS matrix model, but with mass deformation terms breaking the global SO(9) symmetry of the latter to \(\mathrm{SO} (5) \times \mathrm{SO}(3) \times \mathbb{Z}_2\). Introducing an ansatz configuration involving fuzzy four- and two-spheres with collective time dependence, we examine the chaotic dynamics in a family of effective Lagrangians obtained by tracing over the aforementioned ansatz configurations at the matrix levels \(N=\frac{1}{6} (n + 1)(n + 2)(n + 3)\), for \(n = 1, 2, \dots , 7\). Through numerical work, we determine the Lyapunov spectrum and analyze how the largest Lyapunov exponents (LLE) change as a function of the energy, and discuss how our results can be used to model the temperature dependence of the LLEs and put upper bounds on the temperature above which LLE values comply with the Maldacena-Shenker-Stanford (MSS) bound \(2 \pi T\), and below which it will eventually be violated.Quantum-mechanical twin paradox.https://www.zbmath.org/1456.830032021-04-16T16:22:00+00:00"Franson, J. D."https://www.zbmath.org/authors/?q=ai:franson.james-dCausal and causally separable processes.https://www.zbmath.org/1456.810172021-04-16T16:22:00+00:00"Oreshkov, Ognyan"https://www.zbmath.org/authors/?q=ai:oreshkov.ognyan"Giarmatzi, Christina"https://www.zbmath.org/authors/?q=ai:giarmatzi.christinaSpacetime replication of continuous variable quantum information.https://www.zbmath.org/1456.811082021-04-16T16:22:00+00:00"Hayden, Patrick"https://www.zbmath.org/authors/?q=ai:hayden.patrick-m"Nezami, Sepehr"https://www.zbmath.org/authors/?q=ai:nezami.sepehr"Salton, Grant"https://www.zbmath.org/authors/?q=ai:salton.grant"Sanders, Barry C."https://www.zbmath.org/authors/?q=ai:sanders.barry-cErratum to: Vacuum decays around spinning black holes.https://www.zbmath.org/1456.830362021-04-16T16:22:00+00:00"Oshita, Naritaka"https://www.zbmath.org/authors/?q=ai:oshita.naritaka"Ueda, Kazushige"https://www.zbmath.org/authors/?q=ai:ueda.kazushige"Yamaguchi, Masahide"https://www.zbmath.org/authors/?q=ai:yamaguchi.masahideSummary: However, the diagonalized metric is not exactly obtained by the transformation but is valid approximately, which was missed in the original paper. This does not affect our results and conclusion as is explained below.