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
Citations
More filters
Journal ArticleDOI
Building a linear equation-of-state for trapped gravitons from finite size effects and the Schwarzschild black hole case
TL;DR: Viaggiu et al. as discussed by the authors explored the possibility that the frequency of the radiation made of trapped gravitons can be modified in such a way that a linear equation-of-state PV = γU for the pressure P and the internal energy U arises.
Journal ArticleDOI
Bose-Einstein condensation and condensation of q-particles in equilibrium and non equilibrium thermodynamics: a new approach
Luigi Accardi,Francesco Fidaleo +1 more
TL;DR: In this article, it was shown that the condensation can occur both in dimension less than 3 in conguration space, and even in excited energy levels, where the Bose/Fermi alternative is not in thermal equilibrium.
Journal ArticleDOI
Dualities of the entropy bound
TL;DR: In this article, the authors study the hypothetical thermodynamic system which saturates the so-called Hubble entropy bound and show that it is invariant under the S- and T-dualities of string theory as well as the interchanges of the eleventh dimension of M-theory.
Journal ArticleDOI
String-inspired running vacuum — The “Vacuumon”—and the swampland criteria
TL;DR: In this article, the authors show that the vacuumon potential satisfies certain swampland criteria for the relevant regime of parameters and field range, which implies that under certain conditions, the VF can play a role as a quantum field during the inflationary phase of the running vacuum model.
Journal ArticleDOI
Anomalous Galactic Dynamics by Collusion of Rindler and Cosmological Horizons
TL;DR: In this article, it was shown that the onset to weak gravity across galaxies is sharp by causality, and this onset presents a new challenge for canonical dark matter distributions on galactic scales in ΛCDM.