Hawking radiation and thermodynamics of dynamical black holes in phantom dominated universe

TL;DR

This paper explores the thermodynamics of dark energy and black holes in a universe dominated by phantom energy, demonstrating regular thermodynamic quantities across the phantom divide and analyzing accretion processes.

Contribution

It provides a detailed analysis of thermodynamic properties during phantom divide crossing and establishes conditions for the generalized second law in a dark energy universe.

Findings

Thermodynamic quantities remain regular at the phantom divide crossing.

Dark fluid temperature and entropy are always positive.

A negative chemical potential and $w<-5/3$ are required for the second law validity.

Abstract

The thermodynamic properties of dark energy-dominated universe in the presence of a black hole are investigated in the general case of a varying equation-of-state-parameter $w(a)$. We show that all the thermodynamics quantities are regular at the phantom divide crossing, and particularly the temperature and the entropy of the dark fluid are always positive definite. We also study the accretion process of a phantom fluid by black holes and the conditions required for the validity of the generalized second law of thermodynamics. As a results we obtain a strictly negative chemical potential and an equation-of-state parameter $w<-5/3.$