Fuzzy Euclidean wormholes in de Sitter space

TL;DR

This paper explores Euclidean wormholes in de Sitter space within Einstein gravity, revealing their potential dominance over instantons and multiple interpretations related to universe creation, bounce, and singularities.

Contribution

It demonstrates the existence and significance of Euclidean wormholes in de Sitter space, offering new insights into quantum gravity and cosmological models.

Findings

Wormholes can be preferred over Hawking-Moss instantons for certain parameters.

Euclidean wormholes have multiple interpretations related to universe creation and bounces.

Wormholes provide potential resolutions to singularity challenges.

Abstract

We investigate Euclidean wormholes in Einstein gravity with a massless scalar field in de Sitter space. Euclidean wormholes are possible due to the analytic continuation of the time as well as complexification of fields, where we need to impose the classicality after the Wick-rotation to the Lorentzian signatures. For some parameters, wormholes are preferred than Hawking-Moss instantons, and hence wormholes can be more fundamental than Hawking-Moss type instantons. Euclidean wormholes can be interpreted in three ways: (1) classical big bounce, (2) either tunneling from a small to a large universe or a creation of a collapsing and an expanding universe from nothing, and (3) either a transition from a contracting to a bouncing phase or a creation of two expanding universes from nothing. These various interpretations shed some light on challenges of singularities. In addition, these will help to understand tensions between various kinds of quantum gravity theories.