Entropy Bound Derived from the New Thermodynamics on Holographic Screen

We introduce a new interpretation of chemical potential and show that holographic entropy is entropybound,which is supported by two ideal cases discussed in detail.One is sparse but incompressible liquid like a star ofuniform density and the other is a screen at infinity in spherically symmetric spacetime.Our work is based on the newscenario of entropy force and holographic thermodynamics,and the Brown-York quasi-local energy.

Dynamical Horizon Entropy Bound Conjecture in Loop Quantum Cosmology

The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the loop gravity theory and one version of this conjecture. Recently, He and Zhang [J. High Energy Phys. 10 (2007) 077] proposed a version for the dynamical horizon of the universe, which validates the entropy bound conjecture for the cosmology filled with perfect fluid in the classical scenario when the universe is far away from the big bang singularity. However, their conjecture breaks down near big bang region. We examine this conjecture in the context of the loop quantum cosmology. With the example of photon gas, this conjecture is protected by the quantum geometry effects as expected.

Upper bound for the time derivative of entropy for a stochastic dynamical system with double singularities driven by non-Gaussian noise

A stochastic dynamical system with double singularities driven by non-Gaussian noise is investigated. The Fokker Plank equation of the system is obtained through the path-integral approach and the method of transformation. Based on the definition of Shannon＇s information entropy and the Schwartz inequality principle, the upper bound for the time derivative of entropy is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculations can be used to interpret the effects of the system dissipative parameter, the system singularity strength parameter, the noise correlation time and the noise deviation parameter on the upper bound.

A new entropic force scenario and holographic thermodynamics

We propose a new holographic program of gravity in which we introduce a surface stress tensor.Our proposal differs from Verlinde's in several aspects.First,we use an open or a closed screen.Second,the temperature is not necessary,but a surface energy density and pressure are introduced.The surface stress tensor is proportional to the extrinsic curvature.Third,the energy we use is Brown-York energy and the equipartition theorem is violated by a non-vanishing surface pressure.We discuss holographic thermodynamics of a gas of weak gravity and find a chemical potential,and then show that Verlinde's program does not lead to reasonable thermodynamics.The holographic entropy is similar to the Bekenstein entropy bound.