dS$\boldsymbol{_2}$ as excitation of AdS$\boldsymbol{_2}$

TL;DR

This paper introduces a family of 2D dilaton gravity models where de Sitter space emerges as an excitation of Anti-de Sitter space, exploring their thermodynamics, stability, and phase dominance at different temperatures.

Contribution

It presents new models with state-dependent curvature that unify dS$_2$ and AdS$_2$ features, extending the Almheiri--Polchinski framework and analyzing their stability and phase behavior.

Findings

Low temperatures are dominated by AdS$_2$ geometry.

High temperatures are dominated by dS$_2$ geometry.

Models exhibit both perturbative and non-perturbative stability.

Abstract

We introduce a family of 2D dilaton gravity models with state-dependent constant curvature so that dS$_2$ emerges as an excitation of AdS$_2$. Curiously, the strong coupling region corresponds to the asymptotic region geometrically. Apart from these key differences, many features resemble the Almheiri--Polchinski model. We discuss perturbative and non-perturbative thermodynamical stability, bubble nucleation through matter shockwaves, and semiclassical backreaction effects. In some of these models, we find that low temperatures are dominated by AdS$_2$ but high temperatures are dominated by dS$_2$, concurrent with a recent proposal by Susskind.