Regularization of Vacuum Fluctuations and Frame Dependence

TL;DR

This paper examines how regularizing vacuum fluctuations in gravitational backgrounds affects covariance and Lorentz symmetry, highlighting the protective role of covariance against divergences in vacuum energy.

Contribution

It demonstrates that common regularization methods break covariance and emphasizes the importance of covariance in safeguarding vacuum energy from divergences.

Findings

4-momentum cut-off breaks general covariance

Covariance protects vacuum energy from power divergences

Regularization impacts symmetry properties in gravitational backgrounds

Abstract

We discuss the regularization of vacuum fluctuations in a gravitational background. It is shown that general covariance is broken even by a 4-momentum cut-off, consistent with Lorentzian symmetry. It is pointed out that general covariance is a protective symmetry for the vacuum energy from power divergences.