Fluctuations of the flux of energy on the apparent horizon

TL;DR

This paper investigates the statistical fluctuations of energy flux on the apparent horizon of a homogeneous universe, revealing their dependence on temperature and area, and implications for the thermodynamic nature of the universe.

Contribution

It applies the Landau-Lifshiftz fluctuation method to cosmological horizons, providing new insights into their thermodynamic fluctuation behavior.

Findings

Fluctuations increase with horizon temperature.

Fluctuations decrease with horizon area.

Fluctuations vanish in de Sitter space.

Abstract

Adopting the Landau-Lifshiftz method of classical fluctuations we determine the statistical average strength of the fluctuations of the energy flux on the apparent horizon of a homogeneous and isotropic universe described by Einstein gravity. We find that the fluctuations increase with the temperature of the horizon and decrease with its area, in accordance with the features of systems where gravity can be neglected. %is absent. We further find, on the one hand, that the fluctuations vanish in the cosmological constant dominated de Sitter expansion, and, on the other hand, that the domination of phantom fields is excluded. The reasonableness of the results we have obtained lend support to the view that the universe behaves as a normal thermodynamic system.