scholarly journals “Physical process version” of the first law and the generalized second law for charged and rotating black holes

2001 ◽  
Vol 64 (8) ◽  
Author(s):  
Sijie Gao ◽  
Robert M. Wald
Keyword(s):  
Black Holes ◽  
Physical Process ◽  
Second Law ◽  
Generalized Second Law ◽  
Rotating Black Holes

scholarly journals Phantom accretion by black holes and the generalized second law of thermodynamics

2010 ◽  
Vol 33 (5-6) ◽  
pp. 292-295 ◽  
Author(s):  
J.A.S. Lima ◽  
S.H. Pereira ◽  
J.E. Horvath ◽  
Daniel C. Guariento
Keyword(s):  
Black Holes ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Generalized Second Law

scholarly journals ENTROPY OF COSMOLOGICAL BLACK HOLES AND THE GENERALIZED SECOND LAW IN THE PHANTOM-ENERGY-DOMINATED UNIVERSE

2011 ◽  
Vol 20 (02) ◽  
pp. 233-252 ◽  
Author(s):  
KHIREDDINE NOUICER
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equation Of State ◽  
State Parameter ◽  
Phantom Energy ◽  
Energy Conditions ◽  
Second Law ◽  
Brick Wall ◽  
Generalized Second Law ◽  
Equation Of State Parameter

Adopting the thin layer improved brick wall method, we investigate the thermodynamics of a black hole embedded in a spatially flat Friedmann–Robertson–Walker universe. We calculate the temperature and the entropy at every apparent horizon for arbitrary solution of the scale factor. We show that the temperature and entropy display a nontrivial behavior as functions of time. In the case of black holes immersed in a universe driven by phantom energy, we show that for specific ranges of the equation-of-state parameter and apparent horizons the entropy is compatible with the D-bound conjecture, and even the null, dominant and strong energy conditions are violated. In the case of accretion of phantom energy onto a black hole with small Hawking–Hayward quasi-local mass, we obtain an equation-of-state parameter in the range w ≤ -5/3, guaranteeing the validity of the generalized second law.

scholarly journals Black hole hair removal for N = 4 CHL models

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Subhroneel Chakrabarti ◽  
Suresh Govindarajan ◽  
P. Shanmugapriya ◽  
Yogesh K. Srivastava ◽  
Amitabh Virmani
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Microscopic Analysis ◽  
Flat Space ◽  
Special Care ◽  
Hair Removal ◽  
Partition Functions ◽  
Rotating Black Holes

Abstract Although BMPV black holes in flat space and in Taub-NUT space have identical near-horizon geometries, they have different indices from the microscopic analysis. For K3 compactification of type IIB theory, Sen et al. in a series of papers identified that the key to resolving this puzzle is the black hole hair modes: smooth, normalisable, bosonic and fermionic degrees of freedom living outside the horizon. In this paper, we extend their study to N = 4 CHL orbifold models. For these models, the puzzle is more challenging due to the presence of the twisted sectors. We identify hair modes in the untwisted as well as twisted sectors. We show that after removing the contributions of the hair modes from the microscopic partition functions, the 4d and 5d horizon partition functions agree. Special care is taken to present details on the smoothness analysis of hair modes for rotating black holes, thereby filling an essential gap in the literature.

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