Graviton

Quantum mechanics

Theoretical physics

de Sitter–Schwarzschild metric

Schwarzschild radius

Gravitation

Mathematical physics

Boundary (topology)

De Sitter space

Quantum gravity

Perturbation (astronomy)

Classical mechanics

Observable

Cosmological constant

Physics

Massive gravity

Mathematics

Mathematical analysis

Quantum

Anti-de Sitter space

De Sitter universe

Dilaton

Universe

Journal of High Energy Physics

A bstract We study some aspects of the de Sitter version of Jackiw-Teitelboim gravity. Though we do not have propagating gravitons, we have a boundary mode when we compute observables with a fixed dilaton and metric at the boundary. We compute the no-boundary wavefunctions and probability measures to all orders in perturbation theory. We also discuss contributions from different topologies, borrowing recent results by Saad, Shenker and Stanford. We discuss how the boundary mode leads to gravitational corrections to cosmological observables when we add matter. Finally, starting from a four dimensional gravity theory with a positive cosmological constant, we consider a nearly extremal black hole and argue that some observables are dominated by the two dimensional nearly de Sitter gravity dynamics.

Two dimensional nearly de Sitter gravity