scholarly journals Entropy bound in Einstein-Born-Infeld black holes

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
F. T. Falciano ◽  
M. L. Peñafiel ◽  
J. C. Fabris
Keyword(s):  
Black Holes ◽  
Entropy Bound

scholarly journals On Boundedness of Entropy of Photon Gas in Noncommutative Spacetime

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Kazi Ashraful Alam ◽  
Mir Mehedi Faruk
Keyword(s):  
Black Holes ◽  
Distribution Function ◽  
Phase Space ◽  
Partition Function ◽  
Boltzmann Distribution ◽  
Einstein Distribution ◽  
Entropy Bound ◽  
Photon Gas ◽  
Noncommutative Spacetime ◽  
Bose Einstein

Entropy bound for the photon gas in a noncommutative (NC) spacetime where phase space is with compact spatial momentum space, previously studied by Nozari et al., has been reexamined with the correct distribution function. While Nozari et al. have employed Maxwell-Boltzmann distribution function to investigate thermodynamic properties of photon gas, we have employed the correct distribution function, that is, Bose-Einstein distribution function. No such entropy bound is observed if Bose-Einstein distribution is employed to solve the partition function. As a result, the reported analogy between thermodynamics of photon gas in such NC spacetime and Bekenstein-Hawking entropy of black holes should be disregarded.

scholarly journals State of matter at high density and entropy bounds

2015 ◽  
Vol 24 (12) ◽  
pp. 1544016 ◽  
Author(s):  
Ali Masoumi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Simple Model ◽  
Maximum Entropy ◽  
Ordinary Matter ◽  
Homogeneous Cosmology ◽  
Entropy Bound ◽  
Entropy Bounds ◽  
State Of Matter

Entropy of all systems that we understand well is proportional to their volumes except for black holes given by their horizon area. This makes the microstates of any quantum theory of gravity drastically different from the ordinary matter. Because of the assumption that black holes are the maximum entropy states, there have been many conjectures that put the area, defined one way or another, as a bound on the entropy in a given region of spacetime. Here, we construct a simple model with entropy proportional to volume which exceeds the entropy of a single black hole. We show that a homogeneous cosmology filled with this gas exceeds one of the tightest entropy bounds, the covariant entropy bound and discuss the implications.

scholarly journals A COVARIANT ENTROPY BOUND CONJECTURE ON THE DYNAMICAL HORIZON

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2467-2474 ◽  
Author(s):  
SONG HE ◽  
HONGBAO ZHANG
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Upper Bound ◽  
Supermassive Black Holes ◽  
Cosmological Models ◽  
Anthropic Principle ◽  
Holographic Principle ◽  
Cosmological Constant Problem ◽  
Entropy Contribution ◽  
Entropy Bound

We propose, as a compelling pattern for the holographic principle, a covariant entropy bound conjecture for more general dynamical horizons. Then we apply our conjecture to ΛCDM cosmological models, where we find that it imposes a novel upper bound, 10-90, on the cosmological constant for our own universe by taking into account the dominant entropy contribution from supermassive black holes, which thus provides an alternative macroscopic perspective for understanding the long-standing cosmological constant problem. As an intriguing implication of this conjecture, we also discuss the possible profound relation between the present cosmological constant, the origin of mass, and the anthropic principle.

scholarly journals A NOTE ON THE CONNECTION BETWEEN THE UNIVERSAL RELAXATION BOUND AND THE COVARIANT ENTROPY BOUND

2009 ◽  
Vol 18 (05) ◽  
pp. 831-835 ◽  
Author(s):  
ALESSANDRO PESCI
Keyword(s):  
Mechanical Property ◽  
Information Theory ◽  
Black Holes ◽  
Relaxation Times ◽  
Quantum Information Theory ◽  
Conventional System ◽  
Entropy Bound ◽  
Statistical Mechanical ◽  
Classical Thermodynamics ◽  
Limiting Value

A recently formulated universal lower bound to the characteristic relaxation times of perturbed thermodynamic systems, derived from quantum information theory and (classical) thermodynamics and known to be saturated for (certain) black holes, is investigated in the light of the gravity–thermodynamics connection. A statistical-mechanical property, unrelated to gravity, essential for the validity of the generalized covariant entropy bound, namely the existence of a lower-limiting value l* for the size of thermodynamic systems, is found to provide a way to understand this universal relaxation bound, thus regardless of the kind of foundations (i.e. whether conventional or information-based) of the statistical-mechanical description. As a by-product an example of a conventional system (i.e. not a black hole) seemingly saturating the universal relaxation bound is provided.

scholarly journals Entropy bound of horizons for charged and rotating black holes

2015 ◽  
Vol 746 ◽  
pp. 53-58 ◽  
Author(s):  
Wei Xu ◽  
Jia Wang ◽  
Xin-he Meng
Keyword(s):  
Black Holes ◽  
Rotating Black Holes ◽  
Entropy Bound
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