Vacuum fluctuation forces between ultra-thin films

TL;DR

This paper explores how quantum size effects influence vacuum fluctuation forces between ultra-thin films, revealing significant deviations from classical models due to electron confinement and quantum oscillations.

Contribution

It introduces a quantum size effect model for vacuum fluctuation forces using a particle-in-a-box dielectric tensor, contrasting with classical continuum models.

Findings

Quantum size effects cause force variations of 40% to a few percent for 1-10 nm films.

Electron confinement induces quantum oscillations in the vacuum fluctuation force.

Quantum effects can significantly reduce the Casimir force at nanometer-scale separations.

Abstract

We have investigated the role of the quantum size effects in the evaluation of the force caused by electromagnetic vacuum fluctuations between ultra-thin films, using the dielectric tensor derived from the particle in a box model. Comparison with the results obtained by adopting a continuum dielectric model shows that, for film thicknesses of 1-10 nm, the electron confinement causes changes in the force intensity with respect to the isotropic plasma model which range from 40% to few percent depending upon the film electron density and the film separation. The calculated force shows quantum size oscillations, which can be significant for film separation distances of several nanometers. The role of electron confinement in reducing the large distance Casimir force is discussed.