The center-of-mass response of confined systems

TL;DR

This paper demonstrates that in confined systems of identical particles, a parabolic potential ensures a non-dissipative center of mass response, with the density response width influenced by internal properties, exemplified by an ideal harmonic gas.

Contribution

It establishes the importance of parabolic confinement for non-dissipative center of mass responses and analyzes how internal interactions affect the response width.

Findings

Parabolic confinement guarantees non-dissipative center of mass response.

Density response width depends on internal degrees of freedom.

Harmonic interparticle interactions influence the response characteristics.

Abstract

For confined systems of identical particles, either bosons or fermions, we argue that the parabolic nature of the confinement potential is a prerequisite for the non-dissipative character of the center of mass response to a uniform probe. For an excitation in a parabolic confining potential, the half width of the density response function depends nevertheless quantitatively on properties of the internal degrees of freedom, as is illustrated here for an ideal confined gas of identical particles with harmonic interparticle interactions.