Spin-orbit-coupled topological Fulde-Ferrell states of fermions in a harmonic trap

Abstract

Motivated by recent experimental breakthroughs in generating spin-orbit coupling in ultracold Fermi gases using Raman laser beams, we present a systematic study of spin-orbit-coupled Fermi gases confined in a quasi-one-dimensional trap in the presence of an in-plane Zeeman field (which can be realized using a finite two-photon Raman detuning). We find that a topological Fulde-Ferrell state will emerge, featuring finite-momentum Cooper pairing and zero-energy Majorana excitations localized near the edge of the trap based on the self-consistent Bogoliubov-de Genes (BdG) equations. We find analytically the wavefunctions of the Majorana modes. Finally using the time-dependent BdG we show how the finite-momentum pairing field manifests itself in the expansion dynamics of the atomic cloud.

5 pages, 4 figures + 2 pages supplemental material

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Cited by in corpus (7)

• Spin - orbital-angular-momentum coupling in Bose-Einstein condensates
• Quantum phases of Bose-Einstein condensates with synthetic spin - orbital-angular-momentum coupling
• Soliton-induced Majorana fermions in a one-dimensional atomic topological superfluid
• Topological Fulde-Ferrell Superfluids of a Spin-Orbit Coupled Fermi Gas
• Superfluid density and Berezinskii-Kosterlitz-Thouless transition of a spin-orbit coupled Fulde-Ferrell superfluid
• Three-dimensional spin-orbit coupled Fermi gases: Fulde-Ferrell pairing, Majorana fermions, Weyl fermions and gapless topological superfluidity
• Spin-imbalanced ultracold Fermi gases in a two-dimensional array of tubes