Journal ArticleDOI
Universal upper bound on the entropy-to-energy ratio for bounded systems
TLDR
For systems with negligible self-gravity, the bound follows from application of the second law of thermodynamics to a gedanken experiment involving a black hole as discussed by the authors, and it is shown that black holes have the maximum entropy for given mass and size which is allowed by quantum theory and general relativity.Abstract:
We present evidence for the existence of a universal upper bound of magnitude $\frac{2\ensuremath{\pi}R}{\ensuremath{\hbar}c}$ to the entropy-to-energy ratio $\frac{S}{E}$ of an arbitrary system of effective radius $R$. For systems with negligible self-gravity, the bound follows from application of the second law of thermodynamics to a gedanken experiment involving a black hole. Direct statistical arguments are also discussed. A microcanonical approach of Gibbons illustrates for simple systems (gravitating and not) the reason behind the bound, and the connection of $R$ with the longest dimension of the system. A more general approach establishes the bound for a relativistic field system contained in a cavity of arbitrary shape, or in a closed universe. Black holes also comply with the bound; in fact they actually attain it. Thus, as long suspected, black holes have the maximum entropy for given mass and size which is allowed by quantum theory and general relativity.read more
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Random versus holographic fluctuations of the background metric. I. (Cosmological) running of space-time dimension
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Bekenstein-Bound and Information-Based Approach
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Hawking radiation and thermodynamics of dynamical black holes in a phantom-dominated universe
TL;DR: In this article, the authors investigated the thermodynamic properties of a phantom energy-dominated universe in the presence of a black hole in the general case of a varying equation-of-state parameter w(a).
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Minimal length and black hole area quantization
Gia Dvali,Cesar Gomez +1 more
TL;DR: In this article, the authors discuss the implications of the concept of the minimal length, the Planck length, for black hole physics and argue that it naturally leads to quantization of black hole area in Planck units.