Superfluid Signatures in a Dissipative Quantum Point Contact

We measure superfluid transport of strongly interacting fermionic lithium atoms through a quantum point contact with local, spin-dependent particle loss. We observe that the characteristic non-Ohmic superfluid transport enabled by high-order multiple Andreev reflections transitions into an excess Ohmic current as the dissipation strength exceeds the superfluid gap. We develop a model with mean-field reservoirs connected via tunneling to a dissipative site. Our calculations in the Keldysh formalism reproduce the observed nonequilibrium particle current, yet do not fully explain the observed loss rate or spin current.

  • Received 6 October 2022
  • Revised 13 February 2023
  • Accepted 13 April 2023

DOI:https://doi.org/10.1103/PhysRevLett.130.200404

© 2023 American Physical Society

Atomic, Molecular & OpticalCondensed Matter, Materials & Applied PhysicsGeneral Physics

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