No Page Curves for the de Sitter Horizon
Abstract
We investigate the finegrained entropy of the de Sitter cosmological horizon. Starting from threedimensional pure de Sitter space, we consider a partial reduction approach, which supplies an auxiliary system acting as a heat bath both at future infinity and inside the static patch. This allows us to study the timedependent entropy of radiation collected for both observers in the outofequilibrium Unruhde Sitter state, analogous to black hole evaporation for a cosmological horizon. Central to our analysis in the static patch is the identification of a weakly gravitating region close to the cosmological horizon; this is suggestive of a relation between observables at future infinity and inside the static patch. We find that in principle, while the metaobserver at future infinity naturally observes a pure state, the static patch observer requires the use of the island formula to reproduce a unitary Page curve. However, in practice, catastrophic backreaction occurs at the Page time, and neither observer will see unitary evaporation.
 Publication:

arXiv eprints
 Pub Date:
 August 2021
 arXiv:
 arXiv:2108.09318
 Bibcode:
 2021arXiv210809318K
 Keywords:

 High Energy Physics  Theory
 EPrint:
 33 pages, 8 figures