BCS-BEC Crossover in Atomic Fermi Gases with a Narrow Resonance

Abstract

We determine the effects on the BCS-BEC crossover of the energy dependence of the effective two-body interaction, which at low energies is determined by the effective range. To describe interactions with an effective range of either sign, we consider a single-channel model with a two-body interaction having an attractive square well and a repulsive square barrier. We investigate the two-body scattering properties of the model, and then solve the Eagles-Leggett equations for the zero temperature crossover, determining the momentum dependent gap and the chemical potential self-consistently. From this we investigate the dependence of the crossover on the effective range of the interaction.

12 pages, 14 figures

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• Universality in Ultra-Cold Few- and Many-Boson Systems
• Dilute quantum liquid in a K-Rb Bose mixture
• Ab-initio Quantum Monte Carlo study of ultracold atomic mixtures