Amplification phenomena of Casimir force fluctuations on close scatterers coupled via a coherent fermionic fluid

TL;DR

This paper investigates the Casimir force fluctuations on close scatterers in a fermionic fluid, revealing amplification phenomena and oscillating behaviors of force fluctuations, with implications for nanostructures and cold atom systems.

Contribution

It provides a theoretical analysis of Casimir force fluctuations in fermionic fluids, highlighting amplification effects and oscillatory behaviors in close scatterers, which were not previously characterized.

Findings

Force fluctuation variance is significant in both equilibrium and non-equilibrium.

At small separations, an attractive Casimir force acts on the scatterers.

Force fluctuations exhibit oscillations and long-distance behavior similar to single scatterers.

Abstract

We study the mechanical actions affecting close scatterers immersed in a coherent fermionic fluid. Using a scattering field theory, we theoretically analyse the single-scatterer and the two-scatterer case. Concerning the single-scatterer case, we find that a net force affects the scatterer dynamics only in non-equilibrium condition, i.e. imposing the presence of a non-vanishing particle current flowing through the system. The force fluctuation (variance) is instead not negligible both in equilibrium and in non-equilibrium conditions. Concerning the two-scatterer case, an attractive fluid-mediated Casimir force is experienced by the scatterers at small spatial separation, while a decaying attractive/repulsive behavior as a function of the scatterer separation is found. Furthermore, the Casimir force fluctuations acting on a given scatterer in close vicinity of the other present an oscillating behavior reaching a long distance limit comparable to the value of the single-scatterer case. The relevance of these findings is discussed in connection with fluctuation phenomena in low-dimensional nanostructures and cold atoms systems.