Engineering Casimir interactions with epsilon-near-zero materials

TL;DR

This paper demonstrates how the Casimir force between parallel plates can be tuned in both magnitude and sign using epsilon-near-zero materials, enabling potential applications in nanomechanics.

Contribution

It introduces a method to control the Casimir force via dispersive coatings with tunable plasma frequency, allowing continuous force variation and sign reversal.

Findings

Force can be tuned in magnitude and sign.

Continuous force variation achieved with coatings.

Potential for stable and unstable configurations in nanomechanics.

Abstract

In this paper we theoretically demonstrate the tunability of the Casimir force both in sign and magnitude between parallel plates coated with dispersive materials. We show that this force, existing between uncharged plates, can be tuned by carefully choosing the value of the plasma frequency (i.e., the epsilon-near-zero frequency) of the coating in the neighborhood of the resonance frequency of the cavity. The coating layer enables a continuous variation of the force between four limiting values when a coating is placed on each plate. We explore the consequences of such variation when pairs of electric and magnetic conductors (i.e. low and high impedance surfaces) are used as substrates on either side, showing that this continuous variation results in changes in the sign of the force, leading to both stable and unstable conditions, which could find interesting potential applications in nanomechanics including nanoparticle tweezing.