Thermodynamics in Modified Gravity with Curvature Matter Coupling

Abstract

The first and generalized second laws of thermodynamics are studied in f(R,Lm) gravity, a more general modified theory with curvature matter coupling. It is found that one can translate the Friedmann equations to the form of first law accompanied with entropy production term. This behavior is due to the nonequilibrium thermodynamics in this theory. We establish the generalized second law of thermodynamics and develop the constraints on coupling parameters for two specific models. It is concluded that laws of thermodynamics in this modified theory are more general and can reproduce the corresponding results in Einstein, f(R) gravity, and f(R) gravity with arbitrary as well as nonminimal curvature matter coupling.