UV sensitivity of Casimir energy

TL;DR

This paper investigates how ultraviolet (UV) physics influences the Casimir energy in a five-dimensional model, highlighting the impact of different regularization schemes and cutoff effects on the low-energy vacuum energy calculations.

Contribution

It introduces a cutoff regularization scheme with independent UV cutoffs and numerically assesses UV effects on Casimir energy, comparing with zeta-function regularization results.

Findings

UV physics can significantly alter Casimir energy calculations.

Gaussian damping aligns well with traditional zeta-function results.

Kink-type damping can cause notable deviations from standard results.

Abstract

We quantitatively estimate the effect of the UV physics on the Casimir energy in a five-dimensional (5D) model on $S^1/Z_2$. If the cutoff scale of the 5D theory is not far from the compactification scale, the UV physics may affect the low energy result. We work in the cutoff regularization scheme by introducing two independent cutoff scales for the spatial momentum in the non-compact space and for the Kaluza-Klein masses. The effects of the UV physics are incorporated as a damping effect of the contributions to the vacuum energy around the cutoff scales. We numerically calculate the Casimir energy and evaluate the deviation from the result obtained in the zeta-function regularization, which does not include information on the UV physics. We find that the result well agrees with the latter for the Gaussian-type damping, while it can deviate for the kink-type one.