De Sitter Thermodynamics from Diamonds's Temperature

TL;DR

This paper verifies the thermal time hypothesis in de Sitter spacetime, relates it to Minkowski spacetime diamonds, and extends the GEMS picture to finite-lifetime accelerated observers, confirming the thermodynamical nature of spacetime.

Contribution

It demonstrates the validity of the thermal time hypothesis and GEMS picture for finite-lifetime accelerated observers in de Sitter spacetime, extending previous results.

Findings

Thermal time hypothesis holds in de Sitter spacetime.

GEMS picture is valid for finite-lifetime accelerated observers.

Generalizes Minkowski spacetime results to de Sitter spacetime.

Abstract

The thermal time hypothesis proposed by Rovelli [1] regards the physical basis for the flow of time as thermodynamical and provides a definition of the temperature for some special cases. We verify this hypothesis in the case of de Sitter spacetime by relating the uniformly accelerated observer in de Sitter spacetime to the diamond in Minkowski spacetime. Then, as an application of it, we investigate the thermal effect for the uniformly accelerated observer with a finite lifetime in dS spacetime, which generalizes the corresponding result for the case of Minkowski spacetime [2]. Furthermore, noticing that a uniformly accelerated dS observer with a finite lifetime corresponds to a Rindler observer with a finite lifetime in the embedding Minkowski spacetime, we show that the global-embedding-Minkowski-spacetime (GEMS) picture of spacetime thermodynamics is valid in this case. This is a rather nontrivial and unexpected generalization of the GEMS picture, as well as a further verification of both the thermal time hypothesis and the GEMS picture.