Seminarium Fizyki Materii Skondensowanej

Quantized vortices are a hallmark of superfluids. Their generation, dynamics, evolution, and eventual decay have been studied experimentally for some six decades in liquid He and recently in Bose and Fermi cold atom systems. While life cycle of quantized vortices in Bose systems can be described by simple Gross-Pitaevskii equation, Fermi systems are more demanding where satisfactory description requires inclusion of many mechanisms for superfluid relaxation like various phonon processes or Cooper pair breaking. In this talk I will show that time-dependent superfluid density functional theory in natural manner incorporates all these necessary ingredients. Recently, the framework has been extended to spin-imbalanced systems, which allows us to study the superfluid dynamics in new regime where both superfluid and normal components coexist even at zero temperature limit. I will present numerical results for formation and dynamics of a superfluid vortex in the unitary Fermi gas, both in spin balanced and imbalanced cases. Next, I will show that ultra-cold fermionic atoms may provide a new platform for studies of quantum turbulence, accessible to both experiment and theory.