Revisited apparent horizon entropy and GSL in modified gravity

Abstract

This work presents a universal and revisited formalism for the entropy of the apparent horizon in modified gravity to investigate the validity of the Generalized Second Law (GSL) of thermodynamics. This revisited horizon entropy is constructed directly from the modified Friedmann equations in a Friedmann-Robertson-Walker (FRW) universe. The resulting entropy relation contains, beside the standard Bekenstein-Hawking term, an additional integral contribution that encodes the effective energy density and pressure generated by deviations from general relativity. Using this universal entropy formula, a compact expression for the GSL is derived. This formalism is then applied to some viable $f(T)$ and $f(R)$ gravity models, in order to re-evaluate the validity of the GSL as a function of redshift. The analysis demonstrates that including the integral term in the revisited entropy can relatively improve the late-time validity of the GSL for some of these models while living others unchanged, thereby reinforcing the profound connection between thermodynamics and gravity.

23 pages, 2 figures, 2 Tables

References in corpus (54)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Dynamics of dark energy
• f(R) Theories Of Gravity
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• f(R) theories
• Cosmological Constant - the Weight of the Vacuum
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Black Hole Entropy is Noether Charge
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Dark torsion as the cosmic speed-up
• Modified teleparallel gravity: inflation without inflaton
• Einstein's Other Gravity and the Acceleration of the Universe
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Curvature quintessence matched with observational data
• Do consistent $F(R)$ models mimic General Relativity plus $\Lambda$?
• Reconciling dark energy models with f(R) theories
• Thermodynamic Behavior of Friedmann Equation at Apparent Horizon of FRW Universe
• On Born-Infeld Gravity in Weitzenbock spacetime
• Non-equilibrium Thermodynamics of Spacetime
• Observational signatures of f(R) dark energy models that satisfy cosmological and local gravity constraints
• Observational constraints on $f(T)$ theory
• Hawking Radiation of Apparent Horizon in a FRW Universe
• Curing singularities in cosmological evolution of F(R) gravity
• A proof of the generalized second law for rapidly changing fields and arbitrary horizon slices
• $f(T)$ models with phantom divide line crossing
• Non-singular exponential gravity: a simple theory for early- and late-time accelerated expansion
• The dynamical behavior of $f(T)$ theory
• Increase of Black Hole Entropy in Higher Curvature Gravity
• Generalized second law of thermodynamics in f(T) gravity
• Violation of the first law of black hole thermodynamics in $f(T)$ gravity
• Cosmological evolution in exponential gravity
• Aspects of cosmological expansion in F(R) gravity models
• The generalized second law of thermodynamics in the accelerating universe
• $f(T)$ Theories and Varying Fine Structure Constant
• f(T) modified teleparallel gravity models as an alternative for holographic and new agegraphic dark energy models
• The generalized second law in phantom dominated universes in the presence of black holes
• Modified cosmology from the thermodynamics of apparent horizon
• Generalized second law at linear order for actions that are functions of Lovelock densities
• Generic feature of future crossing of phantom divide in viable $f(R)$ gravity models
• Thermodynamics of apparent horizon in modified FRW universe with power-law corrected entropy
• The generalized second law of gravitational thermodynamics on the apparent horizon in f(R)-gravity
• QCD ghost f(T)-gravity model
• f(R) Gravity and its Cosmological Implications
• Universal thermodynamics in different gravity theories: Modified entropy on the horizons
• Phantom crossing in viable $f(R)$ theories
• First law of thermodynamics and entropy of FLRW universe in modified gravity
• Generalised second law beyond the semiclassical regime
• Thermodynamics of a Non-canonical $f(\bar{R},\bar{T})$ gravity
• MOND Theory and Thermodynamics of Spacetime
• Generalized second law of thermodynamics in massive gravity
• Generalized Second Law for Non-minimally Coupled Matter Theories
• Modified cosmology through generalized mass-to-horizon entropy: implications for structure growth and primordial gravitational waves

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