Universal thermodynamics in different gravity theories: Conditions for generalized second law of thermodynamics and thermodynamical equilibrium on the horizons

摘要

The present work deals with a detailed study of universal thermodynamics indifferent modified gravity theories. The validity of the generalized second lawof thermodynamics (GSLT) and thermodynamical equilibrium (TE) of the Universebounded by a horizon (apparent/event) in f(R)-gravity, Einstein-Gauss-Bonnetgravity, RS-II brane scenario and DGP brane model has been investigated. In theperspective of recent observational evidences, the matter in the Universe ischosen as interacting holographic dark energy model. The entropy on thehorizons are evaluated from the validity of the unified first law and as aresult there is a correction (in integral form) to the usual Bekensteinentropy. The other thermodynamical parameter namely temperature on the horizonis chosen as the recently introduced corrected Hawking temperature. The abovethermodynamical analysis is done for homogeneous and isotropic flat FLRW modelof the Universe. The restrictions for the validity of GSLT and the TE arepresented in tabular form for each gravity theory. Finally, due to complicatedexpressions, the validity of GSLT and TE are also examined from graphicalrepresentation, using three Planck data sets.