Cosmological uses of Casimir energy

TL;DR

This paper investigates the potential role of Casimir energy in explaining the cosmological constant, highlighting the importance of topology and regularization methods in obtaining finite, meaningful results.

Contribution

It demonstrates that combining zeta-function and Hadamard regularization techniques yields finite Casimir energy calculations relevant to cosmology.

Findings

Vacuum energy contribution can match observed cosmological constant magnitude

Topology influences the sign of the vacuum energy contribution

Regularization methods recover finite, standard results in Casimir calculations

Abstract

A precise zeta-function calculation shows that the contribution of the vacuum energy to the observed value of the cosmological constant can possibly have the desired order of magnitude albeit the sign strongly depends on the topology of the universe. The non-renormalizable, infinite contributions which have been recently shown to occur when one physically imposes boundary conditions on quantum fields (Casimir calculations) are considered. It is shown that using a Hadamard regularization in addition to the zeta method, the ordinary, finite results in the literature are exactly recovered.