We investigate the response of superfluid Fermi gases to rapid changes of thethree-dimensional s-wave scattering length a by solving the time-dependentBogoliubov-de Gennes equations. In general the magnitude of the order parameter|\Delta| performs oscillations, which are sometimes called the "Higgs" mode,with the angular frequency 2 \Delta_{gap}/ \hbar, where \Delta_{gap} is the gapin the spectrum of fermionic excitations. Firstly, we excite the oscillationswith a linear ramp of 1/a and study the evolution of |\Delta|. Secondly, wecontinously drive the system with a sinusoidal modulation of 1/a. In the firstcase, the oscillations in |\Delta| damp according to a power law. In the secondcase, the continued driving causes revivals in the oscillations. In both cases,the excitation of the oscillations causes a reduction in the time-averagedvalue of |\Delta|. We propose two experimental protocols, based around the twoapproaches, to measure the frequency and damping of the oscillations, and hence\Delta_{gap}.
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