Periodic Reporting for period 1 - VorDIST (Quantum transport in a disordered two-dimensional ultracold Fermi gas)
Berichtszeitraum: 2019-09-01 bis 2021-08-31
A deep understanding of the elementary mechanisms behind quantum vortex energy dissipation has been restricted by the scarcity of experimental signatures. We have addressed this outstanding problem by realizing a programmable vortex collider in a thin, homogeneous fermionic superfluid across the BEC-BCS crossover. We create on-demand vortex configurations and engineer collisions within and between vortex-antivortex pairs. These allow us to decouple dissipation of the vortex energy due to sound emission and due to mutual (thermal) friction. By controlling the dipole sizes for vortex dipole-dipole collisions, we directly visualize how the annihilation of two colliding dipoles radiates a sound pulse, converting the whole energy stored in the swirling field and vortex cores into compressible sound energy. Our experiments provide a comprehensive picture of quantum vortex decay arising from mutual friction, vortex-sound interaction, and a possible contribution from fermionic core-bound states inside a vortex core [3].
[1] W. J. Kwon et al., "Strongly correlated superfluid order parameters from dc Josephson supercurrents", Science 369, 84 (2020).
[2] G. Del Pace et al., "Tunneling Transport of Unitary Fermions across the Superfluid Transition", Physical Review Letters 126, 055301 (2021).
[3] W. J. Kwon et al., "Sound emission and annihilations in a programmable quantum vortex collider" arxiv: 2105.15180 (2021).