Generalized second law and the Bekenstein entropy bound in Gedankenexperiments with black holes

1996 ◽  
Vol 13 (9) ◽  
pp. 2607-2607 ◽  
Author(s):  
O B Zaslavskii
2010 ◽  
Vol 33 (5-6) ◽  
pp. 292-295 ◽  
Author(s):  
J.A.S. Lima ◽  
S.H. Pereira ◽  
J.E. Horvath ◽  
Daniel C. Guariento

2011 ◽  
Vol 20 (02) ◽  
pp. 233-252 ◽  
Author(s):  
KHIREDDINE NOUICER

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.


2004 ◽  
Vol 13 (10) ◽  
pp. 2329-2335
Author(s):  
ANDREW CHAMBLIN ◽  
JOSHUA ERLICH

Just as gravitons can carry energy, they can also be used to transmit information. It follows that an entropy should be associated with gravitational degrees of freedom, independent of the presence or absence of black holes. In this essay, we discuss how one might count gravitational entropy given a classical gravitational field. Our suggestion is motivated by a derivation of the covariant entropy bound in which a gravitational term appears naturally.


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