Finite temperature effective field theory for dark solitons in superfluid Fermi gases

Abstract

We use a finite temperature effective field theory recently developed for superfluid Fermi gases to investigate the properties of dark solitons in these superfluids. Our approach provides an analytic solution for the dip in the order parameter and the phase profile accross the soliton, which can be compared with results obtained in the framework of the Bogoliubov - de Gennes equations. We present results in the whole range of the BCS-BEC crossover, for arbitrary temperatures, and taking into account Gaussian fluctuations about the saddle point. The obtained analytic solutions yield an exact energy-momentum relation for a dark soliton showing that the soliton in a Fermi gas behaves like a classical particle even at nonzero temperatures. The spatial profile of the pair field and for the parameters of state for the soliton are analytically studied. In the strong-coupling regime and/or for sufficiently high temperatures, the obtained analytic solutions match well the numeric results obtained using the Bogoliubov - de Gennes equations.

27 pages, 8 figures

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Cited by in corpus (14)

• Finite temperature effective field theory and two-band superfluidity in Fermi gases
• Universal van der Waals Force Between Heavy Polarons in Superfluids
• Soliton core filling in superfluid Fermi gases with spin-imbalance
• Snake instability of dark solitons across the BEC-BCS crossover: an effective field theory perspective
• Collective modes of a soliton train in a Fermi superfluid
• Finite temperature vortices in a rotating Fermi gas
• Diversified vortex phase diagram for a rotating trapped two-band Fermi gas in the BCS-BEC crossover
• Dark soliton collisions in superfluid Fermi gases
• Verification of an analytic fit for the vortex core profile in superfluid Fermi gases
• Crossover between snake instability and Josephson instability of dark solitons in superfluid Fermi gases
• Vortex and soliton dynamics in particle-hole symmetric superfluids
• Vortex Mass in Superfluid Fermi Gases along the BEC-BCS Crossover
• Vortices in Fermi gases with spin-dependent rotation potentials
• Swallow-tail dispersions of moving solitons in a two-dimensional fermionic superfluid