We study the two-body bound states in a spin-orbital-angular-momentum (SOAM) coupled quantum gas of fermions within a tightly confined ring geometry in two dimensions. Two different configurations are considered: an attractive $s$ -wave interaction exists between two spin species that are SOAM coupled and an atom with SOAM coupled internal spins interacts state selectively with another atom. For both cases, we identify the condition for the emergence of molecular states with finite orbital angular momenta. These molecular states with quantized orbital angular momenta correspond to the SOAM-coupling-induced vortices in the corresponding Fermi superfluid. We propose to detect the molecules through Raman spectroscopy with Laguerre-Gaussian lasers. As the molecular states can form above the superfluid temperature, they offer an experimentally more accessible route toward the study of the underlying pairing mechanism under SOAM coupling.We study the two-body bound states in a spin-orbital-angular-momentum (SOAM) coupled quantum gas of fermions within a tightly confined ring geometry in two dimensions. Two different configurations are considered: an attractive $s$-wave interaction exists between two spin species that are SOAM coupled and an atom with SOAM coupled internal spins interacts state selectively with another atom. For both cases, we identify the condition for the emergence of molecular states with finite orbital angular momenta. These molecular states with quantized orbital angular momenta correspond to the SOAM-coupling-induced vortices in the corresponding Fermi superfluid. We propose to detect the molecules through Raman spectroscopy with Laguerre-Gaussian lasers. As the molecular states can form above the superfluid temperature, they offer an experimentally more accessible route toward the study of the underlying pairing mechanism under SOAM coupling.

arXiv:2203.10834Physical Review AOct 3, 20225 citations

Spinor superfluid currents of exciton-polaritons on a split-ring

Sevak Demirchyan, Igor Yu. Chestnov, Kirill Kondratenko +1 more

Recently, split-ring bosonic condensates of exciton polaritons have been proposed for realisation of qubits. We formulate an analytical model of a polariton condensate in a one-dimensional ring split by a delta-function potential. The persistent current is stopped by the potential defect embedded in a scalar condensate of non-interacting particles, however, it reappears in the presence of an up-critical non-linearity. The nonlinear supercurrents are characterised by fractional orbital momenta while their eigenfunctions may feature grey or dark solitons. The coupling between the spin and the orbital angular momentum of a spinor condensate affects persistent currents crucially. We show that the spin-orbit interaction (SOI) induces the net superfluid current in the condensate with a spatially uniform spin polarisation. We also find solutions where the SOI-induced currents of two spin components of the condensate propagate in opposite directions. The corresponding states of spinor condensates obey a combined mirror reflection and the spin-flip symmetry.Recently, split-ring bosonic condensates of exciton polaritons have been proposed for realisation of qubits. We formulate an analytical model of a polariton condensate in a one-dimensional ring split by a delta-function potential. The persistent current is stopped by the potential defect embedded in a scalar condensate of non-interacting particles, however, it reappears in the presence of an up-critical non-linearity. The nonlinear supercurrents are characterised by fractional orbital momenta while their eigenfunctions may feature grey or dark solitons. The coupling between the spin and the orbital angular momentum of a spinor condensate affects persistent currents crucially. We show that the spin-orbit interaction (SOI) induces the net superfluid current in the condensate with a spatially uniform spin polarisation. We also find solutions where the SOI-induced currents of two spin components of the condensate propagate in opposite directions. The corresponding states of spinor condensates obey a combined mirror reflection and the spin-flip symmetry.

arXiv:2208.14094Aug 30, 20221 citation

Heavy solitons in a fermionic superfluid

Tarik Yefsah, Ariel Sommer, Mark Ku +4 more

arXiv:1302.4736NatureJul 1, 2013173 citations

Heavy Solitons in a Fermionic Superfluid

Martin W. Zwierlein

Bulletin of the American Physical SocietyMar 21, 20130 citations

Generating Giant Vortex in a Fermi Superfluid via Spin-Orbital-Angular-Momentum Coupling

Ke-Ji Chen, Fan Wu, Shi-Guo Peng +2 more

Spin-orbital-angular-momentum (SOAM) coupling has been realized in recent experiments of Bose-Einstein condensates [Chen et al., Phys. Rev. Lett. 121, 113204 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.113204 and Zhang et al., Phys. Rev. Lett. 122, 110402 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.110402], where the orbital angular momentum imprinted upon bosons leads to quantized vortices. For fermions, such an exotic synthetic gauge field can provide fertile ground for fascinating pairing schemes and rich superfluid phases, which are yet to be explored. Here we demonstrate how SOAM coupling stabilizes vortices in Fermi superfluids through a unique mechanism that can be viewed as the angular analog to that of the spin-orbit-coupling-induced Fulde-Ferrell state under a Fermi surface deformation. Remarkably, the vortex size is comparable with the beam waist of Raman lasers generating the SOAM coupling, which is typically much larger than previously observed vortices in Fermi superfluids. With tunable size and core structure, these giant vortex states provide unprecedented experimental access to topological defects in Fermi superfluids.Spin-orbital-angular-momentum (SOAM) coupling has been realized in recent experiments of Bose-Einstein condensates [Chen et al., Phys. Rev. Lett. 121, 113204 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.113204 and Zhang et al., Phys. Rev. Lett. 122, 110402 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.110402], where the orbital angular momentum imprinted upon bosons leads to quantized vortices. For fermions, such an exotic synthetic gauge field can provide fertile ground for fascinating pairing schemes and rich superfluid phases, which are yet to be explored. Here we demonstrate how SOAM coupling stabilizes vortices in Fermi superfluids through a unique mechanism that can be viewed as the angular analog to that of the spin-orbit-coupling-induced Fulde-Ferrell state under a Fermi surface deformation. Remarkably, the vortex size is comparable with the beam waist of Raman lasers generating the SOAM coupling, which is typically much larger than previously observed vortices in Fermi superfluids. With tunable size and core structure, these giant vortex states provide unprecedented experimental access to topological defects in Fermi superfluids.

arXiv:2006.08898Physical Review LettersDec 31, 202021 citations

s

-wave interaction exists between two spin species that are SOAM coupled and an atom with SOAM coupled internal spins interacts state selectively with another atom. For both cases, we identify the condition for the emergence of molecular states with finite orbital angular momenta. These molecular states with quantized orbital angular momenta correspond to the SOAM-coupling-induced vortices in the corresponding Fermi superfluid. We propose to detect the molecules through Raman spectroscopy with Laguerre-Gaussian lasers. As the molecular states can form above the superfluid temperature, they offer an experimentally more accessible route toward the study of the underlying pairing mechanism under SOAM coupling.