Eur. Phys. J. B (2016) 89: 242
https://doi.org/10.1140/epjb/e2016-70379-8

Regular Article

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

¹ Dipartimento di Fisica “E.R. Caianiello”, Università di Salerno, 84084 Fisciano (SA), Italy
² CNR-SPIN Salerno, 84084 Fisciano (SA), Italy

^a e-mail: fromeo@sa.infn.it

Received: 15 June 2016
Received in final form: 9 September 2016
Published online: 9 November 2016

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 noise level 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.