Supershell structure in trapped dilute Fermi gases

TL;DR

This paper demonstrates that dilute trapped Fermi gases exhibit a super-shell structure modulated by a beat mode, influenced by weak interactions, with implications for understanding shell effects in quantum gases.

Contribution

It introduces the concept of super-shell structure in trapped Fermi gases and explains its origin through a semiclassical trace formula considering symmetry breaking.

Findings

Super-shell structure modulates shell fillings in trapped Fermi gases.

Beat mode length and amplitude depend on interaction strength.

Modification of magic numbers due to super-shell effects.

Abstract

We show that a dilute harmonically trapped two-component gas of fermionic atoms with a weak repulsive interaction has a pronounced super-shell structure: the shell fillings due to the spherical harmonic trapping potential are modulated by a beat mode. This changes the ``magic numbers'' occurring between the beat nodes by half a period. The length and amplitude of this beating mode depend on the strength of the interaction. We give a simple interpretation of the beat structure in terms of a semiclassical trace formula for the symmetry breaking U(3) --> SO(3).