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

Abstract

We introduce a family of 2D dilaton gravity models with state-dependent constant curvature so that dS_22 emerges as an excitation of AdS_22. 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_22 but high temperatures are dominated by dS_22, concurrent with a recent proposal by Susskind.