4 research outputs found
No Page curves for the de Sitter horizon
We investigate the fine-grained entropy of the de Sitter cosmological
horizon. Starting from three-dimensional 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 time-dependent entropy of radiation collected for both observers in
the out-of-equilibrium Unruh-de 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 past
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 meta-observer 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.Comment: 33 pages, 8 figures. v2: references added, minor edits. v3: as
published in JHEP. Minor edits. Comments and clarifications added, regarding
e.g. the static patch backreacted dilaton, and the weakly-coupled radiation
regio