Transitions Between de Sitter Minima

TL;DR

This paper explores the cosmological implications of tunneling between de Sitter minima, focusing on the existence of instantons and their impact on universe geometry, with potential observational consequences for cosmic curvature.

Contribution

It analyzes conditions for Coleman-de Luccia and Hawking-Moss instantons in de Sitter transitions and interprets their cosmological significance using a toy model.

Findings

Hawking-Moss instanton dominates when Coleman-de Luccia does not exist.

Resulting cosmologies are not closed in either instanton case.

Observation of positive curvature would challenge the landscape transition hypothesis.

Abstract

We investigate the cosmological signatures of instantons mediating tunneling between de Sitter minima. For generic potentials the Coleman-de Luccia instanton does not necessarily exist; when it does not, the instanton which contributes to the decay rate is the trivial constant solution, known as the Hawking-Moss instanton. With the aid of a toy model we interpret this solution and describe the resulting cosmology. In neither the Coleman-de Luccia nor Hawking-Moss case can the resulting cosmology be closed. An observation of significant positive curvature would therefore rule out the possibility that our universe arose from any transition from a neighboring minimum in the string-theory landscape.