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
Holographic dark energy model and scalar-tensor theories
TL;DR: In this paper, the effect of potential of the scalar field is investigated in the equation of state parameter and it is shown that for various types of potentials, the equation is negative and transition from deceleration to acceleration expansion of the universe is possible.
Journal ArticleDOI
Black holes and everyday physics
TL;DR: In this paper, a judicious application of black hole physics, one can obtain new results in “everyday physics,” for example, black holes yield a quantum universal upper bound on the entropy-to-energy ratio for ordinary thermodynamical systems which was unknown earlier.
Journal ArticleDOI
Quantum State Reduction: Generalized Bipartitions from Algebras of Observables
TL;DR: In this article, the problem of identifying how the quantum state reduces given a restriction on the observables is investigated, and a general algorithm for finding irreducible representations of matrix algebras is presented.
Journal ArticleDOI
The Poisson Bracket on Free Null Initial Data for Gravity
TL;DR: It is pointed out how caustics and generator crossings can be neatly avoided andPoisson brackets on free data are given and on sufficiently regular functions of the solution spacetime geometry these brackets match the Poisson brackets defined on such functions by the Hilbert action via Peierls' prescription.
Journal ArticleDOI
Holographic Shell Model: Stack Data Structure inside Black Holes
TL;DR: In this article, the authors proposed to use bits of information to inhabit the entire black core interior of a black hole, a bit per a light sheet unit interval of order Planck area difference.