Thermal nature of a generic null surface
Abstract
Dynamical properties of a generic null surface are known to have a thermodynamic interpretation. Such an interpretation is completely based on an analogy between the usual law of thermodynamics and structure of gravitational field equation on the surface. Here we materialize this analogy and show that assigning a temperature on the null surface for a local observer is indeed physically relevant. We find that for a local frame, chosen as outgoing massless chargeless particle (or field mode), perceives a "local unstable Hamiltonian" very near to the surface. Due to this it has finite quantum probability to escape through acausal null path which is given by MaxwellBoltzmann like distribution, thereby providing a temperature on the surface.
 Publication:

Physical Review D
 Pub Date:
 December 2021
 DOI:
 10.1103/PhysRevD.104.124080
 arXiv:
 arXiv:2110.12665
 Bibcode:
 2021PhRvD.104l4080D
 Keywords:

 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory;
 Quantum Physics
 EPrint:
 Minor modifications. This work is a tribute to Prof. T. Padmanabhan (19572021), a coauthor of this paper, and it carries the fond memory of our last collaboration with him. To appear in Phys. Rev. D