Spectrum and dynamics of the BCS-BEC crossover from a few-body perspective.
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.
von Stecher
Javier
J
Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309-0440, USA.
Greene
Chris H
CH