Thermodynamics of the FLRW apparent horizon in Einstein-Gauss-Bonnet gravity

Fuente: arXiv
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Main Authors: Sánchez, Luis M., Quevedo, Hernando
Format: Preprint
Published: 2025
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author Sánchez, Luis M.
Quevedo, Hernando
author_facet Sánchez, Luis M.
Quevedo, Hernando
contents We analyze the thermodynamic properties of the apparent horizon of Friedmann-Lemaître-Roberson-Walker (FLRW) spacetimes in Einstein-Gauss-Bonnet gravity. We use the generalized definition of entropy for gravity theories in higher dimensions to determine the main thermodynamic variables and to compare their behavior with the corresponding quantities in Einstein's theory, emphasizing the role of the Gauss-Bonnet coupling constant and the dimension number. By imposing the validity of the laws of thermodynamics, we show that the apparent horizon can be interpreted thermodynamically as a dark energy fluid, independently of the coupling constant and the dimension number. Using the response functions, we determine the adiabatic index and the number of thermally accesible degrees of freedom of the apparent horizon and argue that this leads to a discretization of the Gauss-Bonnet coupling constant.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10255
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Thermodynamics of the FLRW apparent horizon in Einstein-Gauss-Bonnet gravity
Sánchez, Luis M.
Quevedo, Hernando
General Relativity and Quantum Cosmology
We analyze the thermodynamic properties of the apparent horizon of Friedmann-Lemaître-Roberson-Walker (FLRW) spacetimes in Einstein-Gauss-Bonnet gravity. We use the generalized definition of entropy for gravity theories in higher dimensions to determine the main thermodynamic variables and to compare their behavior with the corresponding quantities in Einstein's theory, emphasizing the role of the Gauss-Bonnet coupling constant and the dimension number. By imposing the validity of the laws of thermodynamics, we show that the apparent horizon can be interpreted thermodynamically as a dark energy fluid, independently of the coupling constant and the dimension number. Using the response functions, we determine the adiabatic index and the number of thermally accesible degrees of freedom of the apparent horizon and argue that this leads to a discretization of the Gauss-Bonnet coupling constant.
title Thermodynamics of the FLRW apparent horizon in Einstein-Gauss-Bonnet gravity
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2507.10255