Webinar given by prof. Piotr Magierski (Warsaw University of Technology, Poland) (2022/09/20)

We had an extensive and informative webinar by prof. Piotr Magierski (Warsaw University of Technology, Poland), entitled “Exotic Structures in Superfluids,” at Tokyo Tech, covering from a very pedagogical introduction to superconductivity in Fermionic systems and superfluidity in Bosonic systems, to various topological excitations (such as quantized vorticies, ferrons, FFLO, etc.), including recent findings in spin-imbalanced Unitary Fermi gas (UFG). The seminar was actually delivered not only for Nuclear Theory Group, but also for Cosmology Group (Yamaguchi Lab.) at Tokyo Tech, because topological structures, like cosmic strings, associated with a symmetry breaking in field theoretical contexts for cosmology, are intriguing objects to explore. We are hoping to find something unexplored through the analogy between the smallest and the largest topological defects.

Exotic Structures in Superfluids

by prof. Piotr Magierski (Warsaw University of Technology)
4pm-6pm, on September 20 (Tue), 2022, via Zoom

Abstract:
Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The existence of superfluidity has been experimentally confirmed in many condensed matter systems, in 3He and 4He liquids, in nuclear systems including nuclei and neutron stars, in both fermionic and bosonic cold atoms in traps, and it is also predicted to show up in dense quark matter. The interplay between spin-polarization and superfluidity gives rise to fascinating phenomena manifested in Josephson-pi junction or in exotic phases like FFLO or Sarma (interior gap) phase, which involve nontrivial behavior of the order parameter.

I will present certain aspects of superfluidity in nonequilibrium conditions, which originate from dynamics of the order parameter both in unpolarized and spin-imbalanced systems. In particular, I will discuss certain properties related to the structure and dynamics of quantum vortices in the context of quantum turbulence. Finally, I will describe the possibility of creation of various exotic structures spin-polarized droplets (ferrons), disordered structures and supersolids in superfluid cold atomic gases.