Second law of thermodynamics in nonminimally coupled gravity. (30th December 2020)

• Record Type: Journal Article
• Authors: Azevedo, R. P. L.; Avelino, P. P.
• Is Part Of: Europhysics letters. Volume 132:Number 3(2020)
• Publication Date: 2020-12-30
• Subjects: 04.20.Fy -- 98.80.Jk; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/132/30005
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: In the present work we show that the second law of thermodynamics does not generally hold if the matter and gravitational fields are nonminimally coupled. We demonstrate this result by explicitly computing the evolution of the entropy of the matter fields in the case of a closed homogeneous and isotropic universe filled with dust and radiation, showing that, in this case, the sign of the entropy variation is determined by the evolution of the universe. The preservation of the second law of thermodynamics in these modified theories would require its generalization to account for a gravitational entropy contribution.