A global picture of quantum de Sitter space

TL;DR

This paper explores the quantum structure of eternal de Sitter space, proposing a finite-dimensional Hilbert space framework that preserves de Sitter symmetry and addresses longstanding conceptual tensions.

Contribution

It introduces a global quantum description of de Sitter space with a finite-dimensional Hilbert space invariant under the full de Sitter group, resolving previous conflicts.

Findings

Finite-dimensional Hilbert space for de Sitter quantum states

Invariance under the full de Sitter group

Implications for Boltzmann brains and Poincare recurrences

Abstract

Perturbative gravity about a de Sitter background motivates a global picture of quantum dynamics in `eternal de Sitter space,' the theory of states which are asymptotically de Sitter to both future and past. Eternal de Sitter physics is described by a finite dimensional Hilbert space in which each state is precisely invariant under the full de Sitter group. This resolves a previously-noted tension between de Sitter symmetry and finite entropy. Observables, implications for Boltzmann brains, and Poincare recurrences are briefly discussed.