Shell Effects in the First Sound Velocity of an Ultracold Fermi Gas

TL;DR

This paper predicts that the first sound velocity in an ultracold Fermi gas confined in a microtube exhibits shell effects, with velocity jumps occurring as the system transitions from one to three dimensions, which can be observed experimentally.

Contribution

It introduces the concept of shell effects in the first sound velocity of a confined ultracold Fermi gas during dimensional crossover.

Findings

First-sound velocity depends strongly on system dimensionality.

Shell effects cause jumps in sound velocity during dimensional crossover.

Experimental feasibility with 40K atoms is discussed.

Abstract

We investigate the first sound of a normal dilute and ultracold two-component Fermi gas in a harmonic microtube, i.e. a cylinder with harmonic transverse radial confinement in the length-scale of microns. We show that the velocity of the sound that propagates along the axial direction strongly depends on the dimensionality of the system. In particular, we predict that the first-sound velocity display shell effects: by increasing the density, that is by inducing the crossover from one-dimension to three-dimensions, the first-sound velocity shows jumps in correspondence with the filling of harmonic modes. The experimental achievability of these effects is discussed by considering 40K atoms.