Fermi super-Tonks-Girardeau state for attractive Fermi gases in an optical lattice

TL;DR

This paper proposes a method to realize and study the highly excited Fermi super-Tonks-Girardeau state in ultracold Fermi gases within optical lattices by quenching interactions, supported by Bethe-ansatz calculations.

Contribution

It introduces a way to generate and analyze the Fermi super-Tonks-Girardeau state in optical lattices through interaction quench and provides exact solutions for its energy and dynamics.

Findings

Fermi super-Tonks-Girardeau state can be realized via interaction quench.

Energies of the state approach a common limit at strong interactions.

Efficient transfer from repulsive to attractive regimes demonstrated.

Abstract

We demonstrate that a kind of highly excited state of strongly attractive Hubbard model, named of Fermi super-Tonks-Girardeau state, can be realized in the spin-1/2 Fermi optical lattice system by a sudden switch of interaction from the strongly repulsive regime to the strongly attractive regime. In contrast to the ground state of the attractive Hubbard model, such a state is the lowest scattering state with no pairing between attractive fermions. With the aid of Bethe-ansatz method, we calculate energies of both the Fermi Tonks-Girardeau gas and the Fermi super-Tonks-Girardeau state of spin-1/2 ultracold fermions and show that both energies approach to the same limit as the strength of the interaction goes to infinity. By exactly solving the quench dynamics of the Hubbard model, we demonstrate that the Fermi super-Tonks-Girardeau state can be transferred from the initial repulsive ground state very efficiently. This allows the experimental study of properties of Fermi super-Tonks-Girardeau gas in optical lattices.