Magyar Tudományos Akadémia
(University of Trento)
On the BCS-BEC crossover in 1D trapped cold gases
First we discuss an integrable model of interacting fermions in one dimension that allows a complete description of the crossover from a BCS- to a Bose-like superfluid. This model bridges the Gaudin-Yang model of attractive spin 1/2 fermions to the Lieb-Liniger model of repulsive bosons. We called it the modified Gaudin-Yang model. The system may be driven from a BCS-like state through a molecular Tonks-Girardeau gas close to resonance to a weakly interacting Bose gas of dimers. We study the ground state energy, the elementary density and spin excitations, and the correlation functions. Then we discuss the BCS-BEC crossover at zero temperature using the Boson-Fermion resonance model in one dimension. In the limit of a broad resonance, this model is equivalent to the modified Gaudin-Yang model. Thus we argue that the one-dimensional crossover may be experimentally realized either via the combination of a Feshbach resonance and a confinement induced resonance or using direct photo-association in a two-component Fermi gas with effectively one-dimensional dynamics.
2004. november 30. (kedd) de. 10:00
I. épület Tanácsterem
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