Spectrum and Dynamics of the BCS-BEC crossover from a few-body perspective

Abstract

The spectrum of two spin-up and two spin-down fermions in a trap is calculated using a correlated gaussian basis throughout the range of the BCS-BEC crossover. These accurate calculations provide a few-body solution to the crossover problem. This solution is used to study the time-evolution of the system as the scattering length is changed, mimicking experiments with Fermi gases near Fano-Feshbach resonances. The structure of avoiding crossings in the spectrum allow us to understand the dynamics of the system as a sequence of Landau-Zener transitions. Finally, we propose a ramping scheme to study atom-molecule coherence.

4 pages, final version to appear in PRL

References in corpus (6)

• Observation of Bose-Einstein Condensation of Molecules
• Weakly bound dimers of fermionic atoms
• Molecules of Fermionic Atoms in an Optical Lattice
• Nonequilibrium dynamics and thermodynamics of a degenerate Fermi gas across a Feshbach resonance
• Adiabatic association of ultracold molecules via magnetic field tunable interactions
• Inserting two atoms into a single optical micropotential

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