The Casimir effect: Recent controversies and progress

TL;DR

This paper reviews recent developments in understanding the Casimir effect, including theoretical advances, experimental progress, controversies over temperature corrections, and implications for fundamental physics like dark energy.

Contribution

It provides a comprehensive update on recent theoretical, experimental, and conceptual progress in Casimir physics, including new results and clarifications of longstanding issues.

Findings

Rederived Casimir force as strong-coupling limit of delta-function potentials

Clarified the role of surface divergences in Casimir calculations

Summarized recent experimental and theoretical advances, including temperature correction controversies

Abstract

The phenomena implied by the existence of quantum vacuum fluctuations, grouped under the title of the Casimir effect, are reviewed, with emphasis on new results discovered in the past four years. The Casimir force between parallel plates is rederived as the strong-coupling limit of $\delta$-function potential planes. The role of surface divergences is clarified. A summary of effects relevant to measurements of the Casimir force between real materials is given, starting from a geometrical optics derivation of the Lifshitz formula, and including a rederivation of the Casimir-Polder forces. A great deal of attention is given to the recent controversy concerning temperature corrections to the Casimir force between real metal surfaces. A summary of new improvements to the proximity force approximation is given, followed by a synopsis of the current experimental situation. New results on Casimir self-stress are reported, again based on $\delta$- function potentials. Progress in understanding divergences in the self-stress of dielectric bodies is described, in particular the status of a continuing calculation of the self-stress of a dielectric cylinder. Casimir effects for solitons, and the status of the so-called dynamical Casimir effect, are summarized. The possibilities of understanding dark energy, strongly constrained by both cosmological and terrestrial experiments, in terms of quantum fluctuations are discussed. Throughout, the centrality of quantum vacuum energy in fundamental physics in emphasized.