Friday, March 2, 2012

1111.3442 (Li Wang et al.)

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

Li Wang, Zhihao Xu, Shu Chen
We investigate properties of an excited state of strongly attractive Fermi Hubbard model, in analogue with the super-Tonks-Girardeau state. 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 and can be viewed as a Fermi generalization of super-Tonks-Girardeau state in the optical lattice system. We show that this 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. 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 realized efficiently. This allows the experimental study of properties of Fermi super-Tonks-Girardeau gas in optical lattices.
View original: http://arxiv.org/abs/1111.3442

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