No Page curves for the de Sitter horizon

• Published in: The journal of high energy physics Vol. 2022; no. 3; pp. 40 - 32
• Main Authors: Kames-King, Joshua, Verheijden, Evita M. H., Verlinde, Erik P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2022; Springer Nature B.V; SpringerOpen
• Subjects: 2D Gravity; Approximation; Black holes; Classical and Quantum Gravitation; Elementary Particles; Entropy; Evaporation; Gravity; High energy physics; Horizon; Islands; Models of Quantum Gravity; Phase transitions; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Radiation; Regular Article - Theoretical Physics; Relativity Theory; Spacetime; String Theory; Theoretical physics; Time dependence; Universe; 2D Gravity; Models of Quantum Gravity
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP03(2022)040

A bstract 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 I + 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 I + 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.