scholarly journals From black holes to baby universes in CGHS gravity

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Victor Godet ◽  
Charles Marteau
Keyword(s):  
Black Holes ◽  
Free Energy ◽  
Path Integral ◽  
Matrix Model ◽  
Flat Space ◽  
Higher Dimensions ◽  
Gaussian Ensemble ◽  
Baby Universes ◽  
Extremal Black Holes

Abstract We study $$ \hat{\mathrm{CGHS}} $$ CGHS ̂ gravity, a variant of the matterless Callan-Giddings-Harvey-Strominger model. We show that it describes a universal sector of the near horizon perturbations of non-extremal black holes in higher dimensions. In many respects this theory can be viewed as a flat space analog of Jackiw-Teitelboim gravity. The result for the Euclidean path integral implies that $$ \hat{\mathrm{CGHS}} $$ CGHS ̂ is dual to a Gaussian ensemble that we describe in detail. The simplicity of this theory allows us to compute exact quantities such as the quenched free energy and provides a useful playground to study baby universes, averages and factorization. In particular we derive a “wormhole = diagonal” identity. We also give evidence for the existence of a non-perturbative completion in terms of a matrix model. Finally, flat wormhole solutions in this model are discussed.

scholarly journals Thermodynamics of Dyonic NUT Charged Black Holes with entropy as Noether charge

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Niloofar Abbasvandi ◽  
Masoumeh Tavakoli ◽  
Robert B. Mann
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Black Hole ◽  
Free Energy ◽  
Phase Behaviour ◽  
Charged Black Holes ◽  
Black Hole Spacetimes ◽  
Horizon Entropy ◽  
Transition Structures ◽  
Extremal Black Holes

Abstract We investigate the thermodynamic behaviour of Lorentzian Dyonic Taub-NUT Black Hole spacetimes. We consider two possibilities in their description: one in which their entropy is interpreted to be one quarter of the horizon area (the horizon entropy), and another in which the Misner string also contributes to the entropy (the Noether charge entropy). We find that there can be as many as three extremal black holes (or as few as zero) depending on the choice of parameters, and that the dependence of the free energy on temperature — and the resultant phase behaviour — depends very much on which of these situations holds. Some of the phase behaviour we observe holds regardless of which interpretation of the entropy holds. However another class of phase transition structures occurs only if the Noether charge interpretation of the entropy is adopted.

scholarly journals BABY UNIVERSES AND STRING THEORY

2006 ◽  
Vol 15 (10) ◽  
pp. 1581-1586 ◽  
Author(s):  
ROBBERT DIJKGRAAF ◽  
RAJESH GOPAKUMAR ◽  
HIROSI OOGURI ◽  
CUMRUN VAFA
Keyword(s):  
Black Holes ◽  
Free Energy ◽  
String Theory ◽  
Quantum Gravity ◽  
One Dimension ◽  
Free Fermions ◽  
Yang Mills ◽  
Exact Answer ◽  
Exactly Solvable ◽  
Baby Universes

The description of 4D BPS black holes in terms of branes wrapped on various cycles in a Calabi–Yau space gives us the opportunity to study various issues in quantum gravity in a definite way by means of the worldvolume theory of the branes. In the particular example discussed here, there is a simple worldvolume description in terms of 2D Yang–Mills theory. The latter is an exactly solvable system of free fermions in one dimension. The exact answer for the free energy of this system can be written in a way that suggests an interpretation in terms of contributions from multiple (baby) universes.

scholarly journals New boundary conditions for AdS2

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Victor Godet ◽  
Charles Marteau
Keyword(s):  
Boundary Conditions ◽  
Path Integral ◽  
Flat Space ◽  
Low Energy ◽  
Asymptotic Symmetry ◽  
Coadjoint Action ◽  
Matrix Ensemble ◽  
Virasoro Group ◽  
Random Matrix Ensemble ◽  
Extremal Black Holes

Abstract We describe new boundary conditions for AdS2 in Jackiw-Teitelboim gravity. The asymptotic symmetry group is enhanced to Diff(S1) ⋉ C∞(S1) whose breaking to SL(2, ℝ) × U(1) controls the near-AdS2 dynamics. The action reduces to a boundary term which is a generalization of the Schwarzian theory and can be interpreted as the coadjoint action of the warped Virasoro group. This theory reproduces the low-energy effective action of the complex SYK model. We compute the Euclidean path integral and derive its relation to the random matrix ensemble of Saad, Shenker and Stanford. We study the flat space version of this action, and show that the corresponding path integral also gives an ensemble average, but of a much simpler nature. We explore some applications to near-extremal black holes.

scholarly journals Quantum BMS transformations in conformally flat space-times and holography

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Laura Donnay ◽  
Gaston Giribet ◽  
Felipe Rosso
Keyword(s):  
Hilbert Space ◽  
Black Holes ◽  
Flat Space ◽  
Conformal Killing ◽  
Conformally Flat ◽  
Asymptotically Flat ◽  
Conformal Killing Vectors ◽  
Classical Gravity ◽  
Holographic Description ◽  
Extremal Black Holes

Abstract We define and study asymptotic Killing and conformal Killing vectors in d-dimensional Minkowski, (A)dS, ℝ × Sd−1 and AdS2× Sd−2. We construct the associated quantum charges for an arbitrary CFT and show they satisfy a closed algebra that includes the BMS as a sub-algebra (i.e. supertranslations and superrotations) plus a novel transformation we call ‘superdilations’. We study representations of this algebra in the Hilbert space of the CFT, as well as the action of the finite transformations obtained by exponentiating the charges. In the context of the AdS/CFT correspondence, we propose a bulk holographic description in semi-classical gravity that reproduces the results obtained from CFT computations. We discuss the implications of our results regarding quantum hairs of asymptotically flat (near-)extremal black holes.

scholarly journals CRITICAL BEHAVIOR OF TARGET SPACE MEAN FIELD THEORY

1993 ◽  
Vol 08 (28) ◽  
pp. 2703-2713 ◽  
Author(s):  
MARK WEXLER
Keyword(s):  
Free Energy ◽  
Low Temperature ◽  
Matrix Model ◽  
Mean Field Theory ◽  
Mean Field ◽  
Target Space ◽  
Temperature Phase ◽  
Critical Curves ◽  
Baby Universes ◽  
Low Temperature Phase

Recently, the free energy of the target space mean field (TSMF) matrix model has been calculated in the low temperature phase, order-by-order in a low temperature expansion. The TSMF model is a matrix model whose discrete target space has an infinite coordination number, and whose free energy assumes a universal form, corresponding to baby universes joined into a tree. Here the free energy is summed to all orders, and expressed through a transcendental algebraic equation, using which we analyze the critical phenomena that occur in the TSMF model. There are two critical curves, at which the matter and the geometry become critical, and for which the critical exponents are [Formula: see text] and [Formula: see text], respectively. There is a bi-critical point where the curves meet, at which [Formula: see text].

scholarly journals Quantum extremal islands made easy. Part II. Black holes on the brane

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Hong Zhe Chen ◽  
Robert C. Myers ◽  
Dominik Neuenfeld ◽  
Ignacio A. Reyes ◽  
Joshua Sandor
Keyword(s):  
Black Holes ◽  
Higher Dimensions ◽  
Two Dimensions ◽  
Brane World ◽  
Ensemble Averaging ◽  
Full Page ◽  
Wide Range ◽  
The Right ◽  
High Degree ◽  
Extremal Black Holes

Abstract We discuss holographic models of extremal and non-extremal black holes in contact with a bath in d dimensions, based on a brane world model introduced in [1]. The main benefit of our setup is that it allows for a high degree of analytic control as compared to previous work in higher dimensions. We show that the appearance of quantum extremal islands in those models is a consequence of the well-understood phase transition of RT surfaces, and does not make any direct reference to ensemble averaging. For non-extremal black holes the appearance of quantum extremal islands has the right behaviour to avoid the information paradox in any dimension. We further show that for these models the calculation of the full Page curve is possible in any dimension. The calculation reduces to numerically solving two ODEs. In the case of extremal black holes in higher dimensions, we find no quantum extremal islands for a wide range of parameters. In two dimensions, our results agree with [2] at leading order; however a finite UV cutoff introduced by the brane results in subleading corrections. For example, these corrections result in the quantum extremal surfaces moving further outward from the horizon, and shifting the Page transition to a slightly earlier time.

scholarly journals A 4d $$ \mathcal{N} $$ = 1 Cardy Formula

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Joonho Kim ◽  
Seok Kim ◽  
Jaewon Song
Keyword(s):  
Black Holes ◽  
Free Energy ◽  
Asymptotic Behavior ◽  
High Temperature ◽  
Gauge Theory ◽  
Chemical Potential ◽  
Temperature Limit ◽  
Superconformal Index ◽  
High Temperature Limit ◽  
Cardy Formula

Abstract We study the asymptotic behavior of the (modified) superconformal index for 4d $$ \mathcal{N} $$ N = 1 gauge theory. By considering complexified chemical potential, we find that the ‘high-temperature limit’ of the index can be written in terms of the conformal anomalies 3c − 2a. We also find macroscopic entropy from our asymptotic free energy when the Hofman-Maldacena bound 1/2 < a/c < 3/2 for the interacting SCFT is satisfied. We study $$ \mathcal{N} $$ N = 1 theories that are dual to AdS5 × Yp,p and find that the Cardy limit of our index accounts for the Bekenstein-Hawking entropy of large black holes.

scholarly journals On overspinning of black holes in higher dimensions

2021 ◽  
Vol 31 ◽  
pp. 100758
Author(s):  
Sanjar Shaymatov ◽  
Naresh Dadhich
Keyword(s):  
Black Holes ◽  
Higher Dimensions
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