Astronomy and Astrophysics – Astrophysics – General Relativity and Quantum Cosmology
Scientific paper
2011-12-29
Astronomy and Astrophysics
Astrophysics
General Relativity and Quantum Cosmology
16 pages, 3 figures; minor improvements to presentation
Scientific paper
The Clausius relation between entropy change and heat flux has previously been used to derive Einstein's field equations as an equation of state. In that derivation the entropy is proportional to the area of a local causal horizon, and the heat is the energy flux across the horizon, defined relative to an approximate boost Killing vector. We examine here whether a similar derivation can be given for extensions beyond Einstein gravity to include higher derivative and higher curvature terms. We review previous proposals which, in our opinion, are problematic or incomplete. Refining one of these, we assume that the horizon entropy depends on an approximate local Killing vector in a way that mimics the diffeomorphism Noether charge that yields the entropy of a stationary black hole. We show how this can be made to work if various restrictions are imposed on the nature of the horizon slices and the approximate Killing vector. Also, an integrability condition on the assumed horizon entropy density must hold. This can yield field equations of a Lagrangian constructed algebraically from the metric and Riemann tensor, but appears unlikely to allow for derivatives of curvature in the Lagrangian.
Guedens Raf
Jacobson Ted
Sarkar Sudipta
No associations
LandOfFree
Horizon entropy and higher curvature equations of state does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Horizon entropy and higher curvature equations of state, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Horizon entropy and higher curvature equations of state will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-728273