# Shell-mediated tunnelling between (anti-)de Sitter vacua

## TL;DR

This paper provides an analytical expression for tunnelling amplitudes between (anti-)de Sitter spacetimes separated by a thin shell, exploring complex spacetime structures and proposing a regularization scheme for pre-tunnelling states.

## Contribution

It offers the first exact analytical formula for tunnelling amplitudes in arbitrary dimensions between (anti-)de Sitter vacua with a thin shell.

## Key findings

- Derived an exact expression for tunnelling amplitude
- Analyzed complex spacetime structures involved
- Proposed a regularization scheme for initial configurations

## Abstract

We give an extensive study of the tunnelling between arbitrary (anti-)de Sitter spacetimes separated by an infinitesimally thin relativistic shell in arbitrary spacetime dimensions. In particular, we find analytically an exact expression for the tunnelling amplitude. The detailed spacetime structures that can arise are discussed, together with an effective "regularization scheme" for "before tunnelling" configurations.