Isospin excitations of a trapped 1D gas of attractively interacting fermions

TL;DR

This paper investigates the isospin excitations in a trapped one-dimensional attractive fermion gas, revealing a unique equidistant low-energy spectrum distinct from the uniform case.

Contribution

It derives the conditions for the local density approximation and uncovers a novel equidistant spectrum of quasiparticle excitations in a trapped 1D fermion gas.

Findings

Equidistant low-energy quasiparticle levels identified

Spectrum shows linear momentum dependence

Distinct from Dirac spectrum in uniform systems

Abstract

We consider a gas of fermions with a short-range attractive intercomponent interaction in a parabolic external potential and derive the conditions of the local density approximation. The obtained spectrum of quasiparticle (isospin) excitations shows equidistant low-energy levels, which is equivalent to a linear momentum dependence and is fundamentally different from the ordinary Dirac spectrum in the spatially uniform case.