Collection Number C06011
Collection Date -
Collection Type Conference/School
The question of how to describe a natural ultraviolet cutoff in an expanding space-time is of significance in several respects. First, it concerns the fate of general covariance in the presence of a natural UV cutoff. Second, it concerns the continued generating of degrees of freedom through expansion, which carries with it the possibility of an associated generating of vacuum energy. Finally, through inflation, a natural ultraviolet cutoff may have left observable imprints in the CMB.
I will first argue that the notion of black hole entropy extends universally to causal horizons. Then I will deduce the causal dynamics of spacetime from the equilibrium thermodynamics of causal horizons. Specifically, it will be shown how the Clausius relation dS = dQ/T between entropy change, energy flux, and acceleration temperature for all local causal horizons implies the Einstein equation, with Newton's constant determined by the universal horizon entropy density. Implications, non-equilibrium processes, and relations to AdS/CFT duality will also be discussed.