New perspective on gravity and the dynamics of spacetime

Abstract

The Einstein{Hilbert action has a bulk term and a surface term (which arises from integrating a four divergence). I show that one can obtain Einstein's equations from the surface term alone. This leads to: (i) a novel, completely self-contained, perspective on gravity and (ii) a concrete mathematical framework in which the description of space{ time dynamics by Einstein's equations is similar to the description of a continuum solid in the thermodynamic limit.