scholarly journals Quantum cosmology of generalized two-dimensional dilaton-gravity models

1995 ◽  
Vol 51 (12) ◽  
pp. 6829-6842 ◽  
Author(s):  
James E. Lidsey
Keyword(s):  
Quantum Cosmology ◽  
Gravity Models ◽  
Two Dimensional ◽  
Dilaton Gravity

scholarly journals WEYL INVARIANCE AND SPURIOUS BLACK HOLES IN TWO-DIMENSIONAL DILATON GRAVITY

1994 ◽  
Vol 09 (27) ◽  
pp. 4811-4835 ◽  
Author(s):  
TAKANORI FUJIWARA ◽  
YUJI IGARASHI ◽  
JISUKE KUBO
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Gravity Models ◽  
Conformal Anomaly ◽  
Quantum Level ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Matter Coupling ◽  
Weyl Invariance

In two-dimensional dilaton gravity theories, there may exist a global Weyl invariance which makes the black hole spurious. If the global invariance and the local Weyl invariance of the matter coupling are intact at the quantum level, there is no Hawking radiation. We explicitly verify the absence of anomalies in these symmetries for the model proposed by Callan, Giddings, Harvey and Strominger. The crucial observation is that the conformal anomaly can be cohomologically trivial and so not truly anomalous in such dilaton gravity models.

scholarly journals Two-dimensional black holes in the limiting curvature theory of gravity

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Valeri P. Frolov ◽  
Andrei Zelnikov
Keyword(s):  
Black Holes ◽  
Gravity Models ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
De Sitter ◽  
Curvature Condition ◽  
Curvature Theory ◽  
Theory Of Gravity ◽  
Modified Theory ◽  
Modified Gravity Models

Abstract In this paper we discuss modified gravity models in which growth of the curvature is dynamically restricted. To illustrate interesting features of such models we consider a modification of two-dimensional dilaton gravity theory which satisfies the limiting curvature condition. We show that such a model describes two-dimensional black holes which contain the de Sitter-like core instead of the singularity of the original non-modified theory. In the second part of the paper we study Vaidya type solutions of the model of the limiting curvature theory of gravity and used them to analyse properties of black holes which are created by the collapse of null fluid. We also apply these solutions to study interesting features of a black hole evaporation.

scholarly journals Islands in multiverse models

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Sergio E. Aguilar-Gutierrez ◽  
Aidan Chatwin-Davies ◽  
Thomas Hertog ◽  
Natalia Pinzani-Fokeeva ◽  
Brandon Robinson
Keyword(s):  
Saddle Point ◽  
Quantum Cosmology ◽  
Von Neumann Entropy ◽  
Coarse Grain ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
False Vacuum ◽  
Von Neumann ◽  
Eternal Inflation ◽  
Linear Dilaton

Abstract We consider multiverse models in two-dimensional linear dilaton-gravity theories as toy models of false vacuum eternal inflation. Coupling conformal matter we calculate the Von Neumann entropy of subregions. When these are sufficiently large we find that an island develops covering most of the rest of the multiverse, leading to a Page-like transition. This resonates with a description of multiverse models in semiclassical quantum cosmology, where a measure for local predictions is given by saddle point geometries which coarse-grain over any structure associated with eternal inflation beyond one’s patch.

scholarly journals Constructing AdS2 flow geometries

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Dionysios Anninos ◽  
Damián A. Galante
Keyword(s):  
Thermodynamic Properties ◽  
Parameter Space ◽  
Matter Field ◽  
Gravity Models ◽  
Energy Conditions ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Point Function ◽  
Flow Geometry ◽  
Matter Fields

Abstract We consider two-dimensional geometries flowing away from an asymptotically AdS2 spacetime. Macroscopically, flow geometries and their thermodynamic properties are studied from the perspective of dilaton-gravity models. We present a precise map constructing the fixed background metric from the boundary two-point function of a nearly massless matter field. We analyse constraints on flow geometries, viewed as solutions of dimensionally reduced theories, stemming from energy conditions. Microscopically, we construct computationally tractable RG flows in SYK-type models at vanishing and non-vanishing temperature. For certain regimes of parameter space, the flow geometry holographically encoding the microscopic RG flow is argued to interpolate between two (near) AdS2 spacetimes. The coupling between matter fields and the dilaton in the putative bulk is also discussed. We speculate on microscopic flows interpolating between an asymptotically AdS2 spacetime and a portion of a dS2 world.

scholarly journals THERMODYNAMIC DUALITY BETWEEN RN BLACK HOLE AND 2D DILATON GRAVITY

2008 ◽  
Vol 23 (02) ◽  
pp. 91-98 ◽  
Author(s):  
YUN SOO MYUNG ◽  
YONG-WAN KIM ◽  
YOUNG-JAI PARK
Keyword(s):  
Black Hole ◽  
Thermodynamic Quantities ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Horizon Thermodynamics

All thermodynamic quantities of the Reissner–Nordström (RN) black hole can be obtained from the dilaton and its potential of two-dimensional (2D) dilaton gravity. The dual relations of four thermodynamic laws are also established. Furthermore, the near-horizon thermodynamics of the extremal RN black hole is completely described by the Jackiw–Teitelboim theory which is obtained by perturbing around the AdS2-horizon.

Two-dimensional quantum cosmology: Directions of dynamical and thermodynamic arrows of time

1989 ◽  
Vol 39 (2) ◽  
pp. 462-469 ◽  
Author(s):  
Takeshi Fukuyama ◽  
Masahiro Morikawa
Keyword(s):  
Quantum Cosmology ◽  
Two Dimensional
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