Null Surface Thermodynamics
Abstract
We establish that boundary degrees of freedom associated with a generic codimension one null surface in $D$ dimensional pure Einstein gravity naturally admit a thermodynamical description. The \textit{null surface thermodynamics} which we expect to universally hold is a result of the diffeomorphism invariance of the theory and do not rely on other special features of the null surface. Using standard surface charge analysis and covariant phase space method, we formulate laws of null surface thermodynamics which are local equations over an arbitrary null surface. This thermodynamical system is generally an open system and can be closed only when there is no flux of gravitons through the null surface. Our analysis extends the usual black hole thermodynamics to a universal feature of any area element on a generic null surface. We discuss the relevance of our study for the membrane paradigm and black hole microstates.
 Publication:

arXiv eprints
 Pub Date:
 October 2021
 arXiv:
 arXiv:2110.04224
 Bibcode:
 2021arXiv211004224A
 Keywords:

 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology
 EPrint:
 12 pages