Seeking the Casimir Energy

TL;DR

This paper investigates whether the Casimir energy affects the critical temperature of a superconductor within a cavity, finding no detectable change beyond experimental sensitivity, which is still much higher than the theoretical prediction.

Contribution

It provides an experimental test of the influence of Casimir energy on superconductor critical temperature, with results constraining theoretical models.

Findings

No detectable change in T_c larger than 12 microKelvin.

Theoretically expected change is about 0.025 microKelvin.

Experimental sensitivity is roughly 1000 times higher than the predicted effect.

Abstract

Since its first description in 1948, the Casimir effect has been studied extensively. Standard arguments for its existence hinge on the elimination of certain modes of the electromagnetic field because of the boundary conditions in the Casimir cavity. As such, it has been suggested that the ground state energy of the vacuum within the cavity may be reduced compared to the value outside. Could this have an effect on physical phenomena within the cavity? We study this Casimir energy and probe whether the critical temperature $T_c$ of a superconductor is altered when it is placed in the cavity. We do not detect any change in $T_c$ larger than 12 microKelvin, but theoretically expect a change on the order of 0.025 microKelvin, roughly 1000 times lower than our achieved sensitivity.