Seminarium Optyczne

Quantum vortices occur in a wide range of systems, from atomic Bose–Einstein condensatesto superfluid helium liquids and superconductors. Their dynamics is associated with theonset of dissipation, which makes the superflow no longer persistent [1]. Paradigmaticexamples are the motion of Abrikosov vortices which determines the resistance of the type-IIsuperconductors or the vortex dynamics in helium superfluids, where the mutual frictionbetween the normal and superfluid components plays a key role in superfluid turbulence.In this work, we study the fundamental mechanisms of vortex energy dissipation by realisinga versatile two-dimensional vortex collider in homogeneous atomic Fermi superfluids acrossthe BEC-BCS crossover [2]. We unveil vortex-sound interactions by observing theconversion of the energy of vortex swirling flow into sound energy during vortexcollisions. We visualise vortices annihilating into sound waves, i.e., the ultimate outcome ofsmall-scale vortex collisions, and we find indications of the essential role played by vortexcore-bound fermionic excitations in strongly-correlated fermion superfluids. Ourprogrammable platform opens the route to exploring new pathways for quantum turbulencedecay, vortex by vortex.[