@article{4956dfcbb0e24389bb45bf095d05457d,
title = "Thermodynamics in modified gravity theories",
abstract = "We demonstrate that there exists an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density f(R,φ,X), where R is the Ricci scalar and X is the kinetic energy of a scalar field φ. This comes from a suitable definition of an energy momentum tensor of the {"}dark{"} component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy S is convenient because it takes into account the contribution of the horizon entropy in non-equilibrium thermodynamics as well as an entropy production term.",
keywords = "Modified theories of gravity, cosmology, dark energy, evaporation, quantum aspects of black holes, thermodynamics",
author = "Kazuharu Bamba and Geng, {Chao Qiang} and Shinji Tsujikawa",
note = "Funding Information: K. B. acknowledges the KEK theory exchange program for physicists in Taiwan and the very kind hospitality at KEK and Tokyo University of Science. S. T. thanks for the warm hospitality at National Tsing Hua University where the present work was initiated. The work by K. B. and C. Q. G. is supported in part by the National Science Council of R. O. C. under Grant #s: NSC-95-2112-M-007-059-MY3 and NSC-98-2112-M-007-008-MY3 and National Tsing Hua University under the Boost Program and Grant #s: 97N2309F1 and 99N2539E1. S.T. thanks financial support for the Grant-in-Aid for Scientific Research Fund of the JSPS (No. 30318802) and the Grant-in-Aid for Scientific Research on Innovative Areas (No. 21111006).",
year = "2011",
month = aug,
day = "15",
doi = "10.1142/S0218271811019542",
language = "English",
volume = "20",
pages = "1363--1371",
journal = "International Journal of Modern Physics D",
issn = "0218-2718",
publisher = "World Scientific Publishing Co. Pte Ltd",
number = "8",
}