Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 95: Cold Atomic Gases, Superfluids, Quantum Fluids and Solids
TT 95.3: Vortrag
Donnerstag, 15. März 2018, 15:30–15:45, HFT-FT 131
Dynamics and decay of dark solitons in superfluid Fermi gases — •Wout Van Alphen1, Giovanni Lombardi1, Serghei Klimin1,2, and Jacques Tempere1,3 — 1Universiteit Antwerpen, B-2610 Antwerpen, Belgium — 2State University of Moldova, 2009 Chisinau, Moldova — 3Harvard University, Cambridge, MA 02138, USA
Dark solitons are localized solitary density dips that retain their shape while propagating at a constant velocity. In recent work, we have studied their properties and dynamics in superfluid Fermi gases by means of a recently developed effective field theory that is capable of describing fermionic superfluids across the BEC-BCS crossover regime in a wide temperature domain.
In superfluid gases, dark solitons are subject to an instability mechanism called the snake instability, which makes the soliton decay into vortices if the radial width of the atom cloud is too large. We have estimated the maximal radial size that the atomic cloud can have in order to preserve the soliton stability. An analysis of the effect of population imbalance on this critical size reveals a stabilization of the soliton with increasing imbalance.
We have also simulated the evolution of two counter-propagating solitons to investigate the properties of dark soliton collisions in different conditions of temperature and imbalance. The collisions are demonstrated to introduce a spatial shift into the soliton trajectories and become increasingly more inelastic when moving towards the unitarity regime of the interaction domain.