Physics & Astronomy Colloquium – Dr. Giacomo Roati
About the event
The Department of Physics and Astronomy invites all to a colloquium featuring Dr. Giacomo Roati, CNR-INO and LENS. Dr. Roati will present their talk, “A Quantum Vortex Collider”, Thursday, January 13th, at 12:10 p.m. in Webster 11.
Abstract:
Quantum vortices occur in a wide range of systems, from atomic Bose–Einstein condensates to superfluid helium liquids and superconductors. Their dynamics are associated with the onset of dissipation, which makes the superflow no longer persistent [1]. Paradigmatic examples are the motion of Abrikosov vortices which determines the resistance of the type-II superconductors or the vortex dynamics in helium superfluids, where the mutual friction between 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 realizing a versatile two-dimensional vortex collider in homogeneous atomic Fermi superfluids across the BEC-BCS crossover [2]. We unveil vortex-sound interactions by observing the conversion of the energy of vortex swirling flow into sound energy during vortex collisions. We visualize vortices annihilating into sound waves, i.e., the ultimate outcome of small-scale vortex collisions, and we find indications of the essential role played by vortex-core-bound fermionic excitations in strongly-correlated fermion superfluids. Our programmable platform opens the route to exploring new pathways for quantum turbulence decay, vortex by vortex.
References:
[1] B. I. Halperin et al. International Journal of Modern Physics B Vol. 24, 4039 (2010)
[2] W. J. Kwon et al, Nature 600, 64 (2021)