scholarly journals QUANTUM ENTROPY FUNCTION FROM AdS2/CFT1 CORRESPONDENCE

2009 ◽  
Vol 24 (23) ◽  
pp. 4225-4244 ◽  
Author(s):  
ASHOKE SEN
Keyword(s):  
Black Hole ◽  
Partition Function ◽  
Classical Limit ◽  
Black Hole Entropy ◽  
Entropy Function ◽  
Quantum Entropy ◽  
Extremal Black Hole ◽  
Statistical Entropy ◽  
Specific Relation ◽  
Horizon Geometry

We review and extend recent attempts to find a precise relation between extremal black hole entropy and degeneracy of microstates using AdS 2/ CFT 1 correspondence. Our analysis leads to a specific relation between degeneracy of black hole microstates and an appropriately defined partition function of string theory on the near horizon geometry — named the quantum entropy function. In the classical limit this reduces to the usual relation between statistical entropy and Wald entropy.

A tale of two horizons

2015 ◽  
Vol 93 (9) ◽  
pp. 995-998 ◽  
Author(s):  
Sean Stotyn
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Space Time ◽  
Extremal Black Hole ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Event Horizons ◽  
Extremal Limit ◽  
Horizon Geometry ◽  
Killing Horizons

I revisit the fate of coinciding horizons and the volume between them in the extremal limit of spherically symmetric black holes in four space–time dimensions, focusing on the Schwarzschild – de Sitter black hole for concreteness. The two Killing horizons in the limit space–time that are traditionally identified with the limiting event horizons of the non-extremal black hole are shown to instead be generated by an enhanced symmetry of the near horizon geometry (NHG). This dismantles the interpretation of the four-volume between the horizons remaining finite in the extremal limit. The NHG is reinterpreted as a tangent space–time to the degenerate black hole horizon, and geometrical objects, such as Killing vectors and Killing horizons, are carefully mapped between the bulk and the NHG. The implications for extremal black hole entropy are then discussed.

scholarly journals The statistical mechanics of near-extremal black holes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Luca V. Iliesiu ◽  
Gustavo J. Turiaci
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Partition Function ◽  
Gauge Field ◽  
Dimensional Reduction ◽  
Degrees Of Freedom ◽  
Energy Scale ◽  
Fixed Charge ◽  
Extremal Black Hole ◽  
Extremal Black Holes

Abstract An important open question in black hole thermodynamics is about the existence of a “mass gap” between an extremal black hole and the lightest near-extremal state within a sector of fixed charge. In this paper, we reliably compute the partition function of Reissner-Nordström near-extremal black holes at temperature scales comparable to the conjectured gap. We find that the density of states at fixed charge does not exhibit a gap; rather, at the expected gap energy scale, we see a continuum of states. We compute the partition function in the canonical and grand canonical ensembles, keeping track of all the fields appearing through a dimensional reduction on S2 in the near-horizon region. Our calculation shows that the relevant degrees of freedom at low temperatures are those of 2d Jackiw-Teitelboim gravity coupled to the electromagnetic U(1) gauge field and to an SO(3) gauge field generated by the dimensional reduction.

scholarly journals Near extremal black hole entropy as entanglement entropy viaAdS2/CFT1

2008 ◽  
Vol 77 (6) ◽  
Author(s):  
Tatsuo Azeyanagi ◽  
Tatsuma Nishioka ◽  
Tadashi Takayanagi
Keyword(s):  
Black Hole ◽  
Entanglement Entropy ◽  
Black Hole Entropy ◽  
Extremal Black Hole

scholarly journals EXTREMAL BLACK HOLES AND ELEMENTARY STRING STATES

1995 ◽  
Vol 10 (28) ◽  
pp. 2081-2093 ◽  
Author(s):  
ASHOKE SEN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Entropy ◽  
Extremal Black Hole ◽  
Coupling Constant ◽  
Left Handed ◽  
Quantum Numbers ◽  
Independent Parameters ◽  
Elementary String ◽  
Extremal Black Holes

Some of the extremal black hole solutions in string theory have the same quantum numbers as the Bogomol’nyi saturated elementary string states. We explore the possibility that these black holes can be identified with elementary string excitations. It is shown that stringy effects could correct the Bekenstein-Hawking formula for the black hole entropy in such a way that it correctly reproduces the logarithm of the density of elementary string states. In particular, this entropy has the correct dependence on three independent parameters, the mass and the left-handed charge of the black hole, and the string coupling constant.

SIGNATURES OF AN EMERGENT GRAVITY FROM BLACK HOLE ENTROPY

2009 ◽  
Vol 18 (14) ◽  
pp. 2323-2327
Author(s):  
CENALO VAZ
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Mass Spectrum ◽  
Partition Function ◽  
Ground State ◽  
Degrees Of Freedom ◽  
Thermodynamic Description ◽  
Black Hole Entropy ◽  
Fundamental Particle ◽  
Horizon Radius

The existence of a thermodynamic description of horizons indicates that space–time has a microstructure. While the "fundamental" degrees of freedom remain elusive, quantizing Einstein's gravity provides some clues about their properties. A quantum AdS black hole possesses an equispaced mass spectrum, independent of Newton's constant, G, when its horizon radius is large compared to the AdS length. Moreover, the black hole's thermodynamics in this limit is inextricably connected with its thermodynamics in the opposite (Schwarzschild) limit by a duality of the Bose partition function. G, absent in the mass spectrum, re-emerges in the thermodynamic description through the Schwarzschild limit, which should be viewed as a natural "ground state." It seems that the Hawking–Page phase transition separates fundamental, "particle-like" degrees of freedom from effective, "geometric" ones.

scholarly journals BOUND OF NONCOMMUTATIVITY PARAMETER BASED ON BLACK HOLE ENTROPY

2010 ◽  
Vol 25 (38) ◽  
pp. 3213-3218 ◽  
Author(s):  
WONTAE KIM ◽  
DAEHO LEE
Keyword(s):  
Black Hole ◽  
Gauge Group ◽  
Black Hole Entropy ◽  
Brick Wall ◽  
Statistical Entropy ◽  
Schwarzschild Black Hole ◽  
Cutoff Parameter ◽  
Entropy Satisfying ◽  
Area Law ◽  
Wall Method

We study the bound of the noncommutativity parameter in the noncommutative Schwarzschild black hole which is a solution of the noncommutative ISO(3, 1) Poincaré gauge group. The statistical entropy satisfying the area law in the brick wall method yields a cutoff relation which depends on the noncommutativity parameter. Requiring both the cutoff parameter and the noncommutativity parameter to be real, the noncommutativity parameter can be shown to be bounded as Θ > 8.4 × 10-2lp.

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