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We study the process of absorption or emission of a bosonic collective excitation by a fermionic quasiparticle in a superfluid of paired fermions. From the RPA equation of motion of the bosonic excitation annihilation operator, we obtain an expression of the coupling amplitude of this process which is limited neither to resonant processes nor to the long wavelength limit. We confirm our result by independently deriving it in the functional integral approach using the gaussian fluctuation approximation, and by comparing it in the long wavelength limit to the quantum hydrodynamic result. Last, we give a straightforward application of the coupling amplitude we obtain by calculating the lifetime of the bosonic excitations of arbitrary wave number. We find a mode quality factor that decreases from its maximum at low wave numbers and vanishes when the bosonic branch hits the pair-breaking continuum.
In processes when particles such as nanodroplets, clusters, or molecules move through a dilute background gas and undergo capture collisions, it is often important to know how much translational kinetic energy is deposited into the particles by these
We propose and demonstrate a momentum filter for atomic gas based on a designed Talbot-Lau interferometer. It consists in two identical optical standing wave pulses separated by a delay equal to odd multiples of the half Talbot time. The one dimensio
We study the time-dependent response of a cold atom cloud illuminated by a laser beam immediately after the light is switched on experimentally and theoretically. We show that cooperative effects, which have been previously investigated in the decay
A proposed paradigm for out-of-equilibrium quantum systems is that an analogue of quantum phase transitions exists between parameter regimes of qualitatively distinct time-dependent behavior. Here, we present evidence of such a transition between dyn
We characterize the collective modes of a soliton train in a quasi-one-dimensional Fermi superfluid, using a mean-field formalism. In addition to the expected Goldstone and Higgs modes, we find novel long-lived gapped modes associated with oscillatio