The central dogma and cosmological horizons

TL;DR

This paper investigates whether the black hole central dogma extends to cosmological horizons, proposing a new extremization approach that aligns with expected quantum properties of de Sitter space.

Contribution

It introduces a two-sided extremization prescription for cosmological horizons, providing a framework consistent with quantum de Sitter space properties and extending black hole holographic ideas.

Findings

Vanishing total entropy for de Sitter space

Entropy of a static patch matches A/4G_N

Island transition occurs at half the horizon size

Abstract

The central dogma of black hole physics -- which says that from the outside a black hole can be described in terms of a quantum system with exp$(\text{Area}/4G_N)$ states evolving unitarily -- has recently been supported by computations indicating that the interior of the black hole is encoded in the Hawking radiation of the exterior. In this paper, we probe whether such a dogma for cosmological horizons has any support from similar computations. The fact that the de Sitter bifurcation surface is a minimax surface (instead of a maximin surface) causes problems with this interpretation when trying to import calculations analogous to the AdS case. This suggests anchoring extremal surfaces to the horizon itself, where we formulate a two-sided extremization prescription and find answers consistent with general expectations for a quantum theory of de Sitter space: vanishing total entropy, an entropy of $A/4G_N$ when restricting to a single static patch, an entropy of a subregion of the horizon which grows as the region size grows until an island-like transition at half the horizon size when the entanglement wedge becomes the entire static patch interior, and a de Sitter version of the Hartman-Maldacena transition.