A violation of the covariant entropy bound?

Abstract

Several arguments suggest that the entropy density at high energy density $\rho$ should be given by the expression $s=K\sqrt{\rho /G}$, where $K$ is a constant of order unity. On the other hand the covariant entropy bound requires that the entropy on a light sheet be bounded by $A/4G$, where $A$ is the area of the boundary of the sheet. We find that in a suitably chosen cosmological geometry, the above expression for $s$ violates the covariant entropy bound. We consider different possible explanations for this fact; in particular the possibility that entropy bounds should be defined in terms of volumes of regions rather than areas of surfaces.

arXiv comment21 pages, 10 figures, More general derivation given, comments about viscosity effects added

References in corpus (40)

• Microscopic Origin of the Bekenstein-Hawking Entropy
• Viscosity in Strongly Interacting Quantum Field Theories from Black Hole Physics
• The holographic principle
• A Covariant Entropy Conjecture
• A Correspondence Principle for Black Holes and Strings
• Cosmic Holography
• Relative entropy and the Bekenstein bound
• Statistical interpretation of Bekenstein entropy for systems with a stretched horizon
• Nonextremal Black Hole Microstates and U-duality
• Brane Gases in the Early Universe
• Proof of Classical Versions of the Bousso Entropy Bound and of the Generalized Second Law
• Self Gravitating Fundamental Strings
• Entropy of 4D Extremal Black Holes
• Holography, Cosmology and the Second Law of Thermodynamics
• Statistical Entropy of Nonextremal Four-Dimensional Black Holes and U-Duality
• Cosmology vs. Holography
• Pre-bangian origin of our entropy and time arrow
• Holographic Cosmology 3.0
• Remarks on Tachyon Driven Cosmology
• Prospects of Inflation
• Proof of a Quantum Bousso Bound
• Entropy on a null surface for interacting quantum field theories and the Bousso bound
• A Causal Entropy Bound
• An Uncertainty Relation of Space-Time
• Notes on Spacetime Thermodynamics and the Observer-dependence of Entropy
• Simple sufficient conditions for the generalized covariant entropy bound
• Brane gas cosmology in M-theory: late time behavior
• A Quantum Bousso Bound
• Fractional Brane State in the Early Universe
• Microscopic Quantum Mechanics of the p=ρUniverse
• On the Status of Highly Entropic Objects
• A Model for the Big Bounce
• Comments on a Covariant Entropy Conjecture
• A Principle to Determine the Number (3 + 1) of Large Spacetime Dimensions
• A Stringy Correspondence Principle in Cosmology
• Holographic Principle during Inflation and a Lower Bound on Density Fluctuations
• Bekenstein-Hawking entropy in expanding universes from black hole theorems
• Causal Entropy Bound for Non-Singular Cosmologies
• An equation of state in the limit of high densities
• Dualities of the entropy bound

Cited by in corpus (2)

• Microphysical manifestations of viscosity and consequences for anisotropies in the very early universe
• Finite Matter Resolution of the Cosmological Entropy Problem