Thermodynamics in modified gravity theories

Kazuharu Bamba*, Chao Qiang Geng, Shinji Tsujikawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)1363-1371
Number of pages9
JournalInternational Journal of Modern Physics D
Issue number8
Publication statusPublished - 2011 Aug 15
Externally publishedYes


  • Modified theories of gravity
  • cosmology
  • dark energy
  • evaporation
  • quantum aspects of black holes
  • thermodynamics

ASJC Scopus subject areas

  • Mathematical Physics
  • Astronomy and Astrophysics
  • Space and Planetary Science


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