17-22 July 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

Imprinting persistent currents in fermionic superfluid rings

19 Jul 2022, 17:00
1h 30m
Hart House (Hart House)

Hart House

Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Degenerate gases, many-body physics, and quantum simulation Poster session


Persistent currents in a ring are one of the most striking manifestations of a quantum system coherence. The periodic boundary constrains the wavefunction phase to wind in a loop of an integer multiple of 2$\pi$, which, when non-zero, gives rise to a current. Besides being a proxy of quantum phase coherence, persistent currents represent a cornerstone for many applications, from precision sensing to quantum computing, that require a fast and controlled current injection and a reliable read-out of its magnitude. Here I present the experimental realization of a fast and on-demand generation of persistent currents in atomic Fermi superfluid rings and the investigation of the connection between their damping and vortex nucleation. We excite persistent current states of on-demand winding number by dynamically imprinting the phase winding in the ring with a tailored laser beam and we read-out the current state via an interferometric probe, which directly accesses the ring phase profile. We demonstrate our method to efficiently excite persistent currents of finite and controllable winding in the different interaction regimes of the BEC-BCS crossover. We then induce the current decay by inserting a small defect in the ring. For currents higher than a critical value, the obstacle triggers the emission of vortices that reduce the phase winding. Our work demonstrates fast and accurate control of persistent currents in fermionic superfluids, opening the route for their application in quantum technologies.

Presenter name Giulia Del Pace

Primary authors

Giulia Del Pace (EPFL) Klejdja Xhani (INO-CNR and LENS) Alessandro Muzi Falconi (Università degli Studi di Trieste) Marco Fedrizzi (INO-CNR and LENS) Nicola Grani (INO-CNR and LENS) Diego Hernandez Rajkov (INO-CNR and LENS) Massimo Inguscio (Campus Biomedico di Roma, INO-CNR and LENS) Francesco Scazza (Università degli Studi di Trieste) Woo Jin Kwon (INO-CNR and LENS) Giacomo Roati (INO-CNR and LENS)

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