Casimir effect for a spherical shell in de Sitter spacetime with signature change

TL;DR

This paper calculates the Casimir stress on a spherical shell in de Sitter spacetime with signature change, revealing effects that induce rapid bubble expansion due to the signature transition.

Contribution

It introduces the calculation of Casimir stress in a signature-changing de Sitter background, highlighting the impact of signature change on bubble dynamics.

Findings

Signature change causes a transient rapid expansion of bubbles.

Casimir stress differs inside and outside the shell based on background metrics.

Signature transition significantly influences quantum field effects in curved spacetime.

Abstract

The Casimir stress on a spherical shell in de Sitter signature changing background for massless scalar field satisfying Dirichlet boundary conditions on the shell is calculated. The Casimir stress is calculated for inside and outside of the shell with different backgrounds corresponding to different metric signatures and cosmological constants. An important contribution appears due to signature change which leads to a transient rapid expansion of the bubbles in this background.