Two super-Tonks-Girardeau states of a trapped one-dimensional spinor Fermi gas

摘要

A harmonically trapped ultracold ID spinor Fermi gas with a strongly attractive ID even-wave interactioninduced, by a 3D Feshbach resonance is studied. It is shown that it has two different super Tonks-Girardeau(sTG) energy eigenstates which are metastable against collapse in spite of the strong attraction, due to their closeconnection with ID hard sphere Bose gases which are highly excited gaslike states. One of these sTG states is ahybrid between an sTG gas with strong (↑↓) attractions and an ideal Fermi gas with no (↑↑) or (↓↓) interactions,the sTG component being an exact analog of the recently observed sTG state of a ID ultracold Bose gas. Itshould be possible to create it experimentally by a sudden switch of the (↑↓) interaction from strongly repulsiveto strongly attractive, as in the recent Innsbruck experiment on the bosonic sTG gas. The other is a trappedanalog of a recently predicted sTG state which is an ultracold gas of strongly bound (t ) fermion dimers whichbehave as bosons with a strongly attractive boson-boson interaction leading to sTG behavior. It is proved thatthe probability of a transition from the ground state for strongly repulsive interaction to this dimer state under asudden switch from strongly repulsive to strongly attractive interaction is 1, contrary to a previous suggestion.