How to modify the van der Waals and Casimir forces without change of dielectric permittivity

TL;DR

This paper proposes an experiment to measure how the Casimir force can be altered by the insulator-metal transition in doped semiconductors, potentially allowing force modification without changing dielectric permittivity.

Contribution

It introduces a novel experimental setup to observe Casimir force changes across the insulator-metal transition, highlighting significant differences between theoretical models.

Findings

Predicted measurable differences in Casimir force due to insulator-metal transition.

Potential to modify van der Waals and Casimir forces without altering dielectric permittivity.

Experimental feasibility with existing laboratory setups.

Abstract

We propose a new experiment on measuring the Casimir force and its gradient between an Au-coated sphere and two different plates made of doped semiconductors. The concentrations of charge carriers in the plates are chosen slightly below and above the critical density at which the Mott-Anderson insulator-metal transition occurs. We calculate changes in the Casimir force and the Casimir pressure due to the insulator-metal transition using the standard Lifshitz theory and the phenomenological approach neglecting the contribution of free charge carriers in the dielectric permittivity of insulator materials (this approach was recently supported by the measurement data of several experiments). It is demonstrated that for the special selection of semiconductor materials (S- or Se-doped Si, B-doped diamond) calculation results using both theoretical approaches differ significantly and the predicted effects are easily detectable using the existing laboratory setups. In the case that the prediction of the phenomenological approach is confirmed, this would open opportunities to modify the van der Waals and Casimir forces with almost no change of room-temperature dielectric permittivity.