Proposal to measure the Casimir Effect Across the Superconducting Transition

The influence of the superconducting transition on the Casimir effect remains experimentally elusive. We propose a novel approach to address this challenge, exploiting the first-order superconducting transition induced in a thick film by a parallel magnetic field. Our calculations for a Au sphere opposite a Pb film, based on the Mattis-Bardeen theory, predict a jump in the Casimir force across the transition. By periodically modulating the magnetic field, we induce a corresponding modulation of the Casimir force that should be readily detectable with existing micro-torsional oscillator technology, opening a promising pathway to finally observe the long-sought Casimir-superconductivity coupling. A successful measurement of this effect would provide crucial insights into the fundamental nature of the Casimir force and its interaction with macroscopic quantum phenomena.