arXiv:cond-mat/0507540 · Physical Review A

Dynamic response of an ultracold Fermi gas near the Feshbach resonance

Wei Yi, L.-M. Duan

Published Jan 1, 2006• 12 citations

Abstract

We investigate the dynamic response of a highly degenerate ultracold Fermi gas to varying magnetic fields near the Feshbach resonance. Following the experimental practice, we calculate the dynamics of the excitation gap in response to the oscillating and linearly ramped magnetic fields, respectively. For oscillating magnetic fields, depending on the frequencies and the amplitudes of the oscillations, the response of the system shows either linear or rich nonlinear behavior. In addition, both the spectral studies through the linear-response theory and the time-domain simulations suggest the existence of a resonant frequency corresponding to the dissociation threshold of the fermion atom pairs. For linearly ramped magnetic fields, the response of the excitation gap shows damped oscillations, with the final value dependent on the rate of the field sweep. This work may find its applications in exploring the dynamics of the ultracold atom superfluidity near the BCS--Bose-Einstein-condensation crossover region.

DOI: 10.1103/physreva.73.013609

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