A Menagerie of Wormholes and Cosmologies in the Gravitational Path Integral

TL;DR

This paper explores various Euclidean gravitational solutions, including wormholes and oscillatory saddles, in AdS contexts, analyzing their phase transitions, cosmological continuations, and implications for universe probabilities.

Contribution

It introduces a comprehensive analysis of diverse gravitational saddles, including exotic wormholes, and their role in cosmological models within Einstein-Scalar-Maxwell theories.

Findings

Identification of phase transitions between different Euclidean saddles.

Analytic continuation of wormholes to Lorentzian FLRW universes with inflation.

Estimation of probability ratios for various cosmological outcomes.

Abstract

We analyse a variety of Euclidean saddles in the gravitational path integral, with asymptotic AdS boundary conditions, in a class of Einstein-Scalar-Maxwell models. These include single boundary solutions, usual and wineglass wormholes, as well as more exotic (quasi)-oscillatory saddles. Our construction shows how an unbound number of oscillations gets tamed, when flat directions of the potential get lifted. We find several interesting phase transitions between these solutions. The Euclidean wormhole backgrounds can be analytically continued to Lorentzian FLRW universes. Some of them contain an early period of inflation. We delineate the conditions under which they can be the dominant saddles in the gravitational path integral and use them to estimate ratios of probabilities for different cosmological outcomes.