1
|
Banger P, Kumar RK, Roy A, Gautam S. Effective potentials in a rotating spin-orbit-coupled spin-1 spinor condensate. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 35:045401. [PMID: 36541536 DOI: 10.1088/1361-648x/aca7a9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
We theoretically study the stationary-state vortex lattice configurations of rotating spin-orbit (SO)- and coherently-coupled spin-1 Bose-Einstein condensates (BECs) trapped in quasi-two-dimensional harmonic potentials. The combined effects of rotation, SO and coherent couplings are analyzed systematically from the single-particle perspective. Through the single-particle Hamiltonian, which is exactly solvable for one-dimensional coupling, we illustrate that a boson in these rotating SO- and coherently-coupled condensates are subjected to effective toroidal, symmetric double-well, or asymmetric double-well potentials under specific coupling and rotation strengths. In the presence of mean-field interactions, using the coupled Gross-Pitaevskii formalism at moderate to high rotation frequencies, the analytically obtained effective potential minima and the numerically obtained coarse-grained density maxima position are in excellent agreement. On rapid rotation, we further find that the spin-expectation per particle of an antiferromagnetic spin-1 BEC approaches unity indicating a similarity in the response with ferromagnetic SO-coupled condensates.
Collapse
Affiliation(s)
- Paramjeet Banger
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - R Kishor Kumar
- Department of Physics, Centre for Quantum Science, and Dodd-Walls Centre for Photonic and Quantum Technologies, University of Otago, Dunedin 9054, New Zealand
| | - Arko Roy
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075 (H.P.), India
| | - Sandeep Gautam
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| |
Collapse
|
2
|
Cai Y, Allman DG, Sabharwal P, Wright KC. Persistent Currents in Rings of Ultracold Fermionic Atoms. PHYSICAL REVIEW LETTERS 2022; 128:150401. [PMID: 35499879 DOI: 10.1103/physrevlett.128.150401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 12/31/2021] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
We have produced persistent currents of ultracold fermionic atoms trapped in a ring, with lifetimes greater than 10 sec in the strongly interacting regime. These currents remain stable well into the BCS regime at sufficiently low temperature. We drive a circulating BCS superfluid into the normal phase and back by changing the interaction strength and find that the probability for quantized superflow to reappear is remarkably insensitive to the time spent in the normal phase and the minimum interaction strength. After ruling out spontaneous current formation for our experimental conditions, we argue that the reappearance of superflow is due to weak damping of normal currents in this limit. These results establish that ultracold fermionic atoms with tunable interactions can be used to create matter-wave circuits similar to those previously created with weakly interacting bosonic atoms.
Collapse
Affiliation(s)
- Yanping Cai
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Daniel G Allman
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Parth Sabharwal
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Kevin C Wright
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| |
Collapse
|
3
|
Wang LL, Ji AC, Sun Q, Li J. Exotic Vortex States with Discrete Rotational Symmetry in Atomic Fermi Gases with Spin-Orbital-Angular-Momentum Coupling. PHYSICAL REVIEW LETTERS 2021; 126:193401. [PMID: 34047615 DOI: 10.1103/physrevlett.126.193401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
We investigate the superfluidity of a two-component Fermi gas with spin-orbital-angular-momentum coupling (SOAMC). Because of the intricate interplay of SOAMC, two-photon detuning and atom-atom interaction, a family of vortex ground states emerges in a broad parameter regime of the phase diagram, in contrast to the usual case where an external rotation or magnetic field is generally required. More strikingly, an unprecedented vortex state, which breaks the continuous rotational symmetry to a discrete one spontaneously, is predicted to occur. The underlying physics are elucidated and verified by numerical simulations. The unique density distributions of the predicted vortex states enable a direct observation in experiment.
Collapse
Affiliation(s)
- Liang-Liang Wang
- School of Science, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - An-Chun Ji
- Department of Physics, Key Lab of Terahertz Optoelectronics (MoE), Capital Normal University, Beijing 100048, China
| | - Qing Sun
- Department of Physics, Key Lab of Terahertz Optoelectronics (MoE), Capital Normal University, Beijing 100048, China
| | - Jian Li
- School of Science, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| |
Collapse
|
4
|
Chen L, Zhang Y, Pu H. Spin-Nematic Vortex States in Cold Atoms. PHYSICAL REVIEW LETTERS 2020; 125:195303. [PMID: 33216592 DOI: 10.1103/physrevlett.125.195303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
The (pseudo)spin degrees of freedom greatly enriches the physics of cold atoms. This is particularly so for systems with high spins (i.e., spin quantum number larger than 1/2). For example, one can construct not only the rank-1 spin vector, but also the rank-2 spin tensor in high spin systems. Here we propose a simple scheme to couple the spin tensor and the center-of-mass orbital angular momentum in a spin-1 cold atom system and show that this leads to a new quantum phase of the matter: the spin-nematic vortex state that features vorticity in an SU(2) spin-nematic tensor subspace. Under proper conditions, such states are characterized by quantized topological numbers. Our work opens up new avenues of research in topological quantum matter with high spins.
Collapse
Affiliation(s)
- Li Chen
- Institute of Theoretical Physics and State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
| | - Yunbo Zhang
- Key Laboratory of Optical Field Manipulation of Zhejiang Province and Physics Department of Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Han Pu
- Department of Physics and Astronomy, and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| |
Collapse
|
5
|
Weiss LS, Borgh MO, Blinova A, Ollikainen T, Möttönen M, Ruostekoski J, Hall DS. Controlled creation of a singular spinor vortex by circumventing the Dirac belt trick. Nat Commun 2019; 10:4772. [PMID: 31619679 PMCID: PMC6795882 DOI: 10.1038/s41467-019-12787-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 10/01/2019] [Indexed: 11/18/2022] Open
Abstract
Persistent topological defects and textures are particularly dramatic consequences of superfluidity. Among the most fascinating examples are the singular vortices arising from the rotational symmetry group SO(3), with surprising topological properties illustrated by Dirac's famous belt trick. Despite considerable interest, controlled preparation and detailed study of vortex lines with complex internal structure in fully three-dimensional spinor systems remains an outstanding experimental challenge. Here, we propose and implement a reproducible and controllable method for creating and detecting a singular SO(3) line vortex from the decay of a non-singular spin texture in a ferromagnetic spin-1 Bose-Einstein condensate. Our experiment explicitly demonstrates the SO(3) character and the unique spinor properties of the defect. Although the vortex is singular, its core fills with atoms in the topologically distinct polar magnetic phase. The resulting stable, coherent topological interface has analogues in systems ranging from condensed matter to cosmology and string theory.
Collapse
Affiliation(s)
- L S Weiss
- Department of Physics and Astronomy, Amherst College, Amherst, MA, 01002-5000, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, 20723, USA
| | - M O Borgh
- Faculty of Science, University of East Anglia, Norwich, NR4 7TJ, UK
| | - A Blinova
- Department of Physics and Astronomy, Amherst College, Amherst, MA, 01002-5000, USA
- Department of Physics, University of Massachusetts, Amherst, MA, 01003, USA
| | - T Ollikainen
- Department of Physics and Astronomy, Amherst College, Amherst, MA, 01002-5000, USA
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
| | - M Möttönen
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044, VTT, Finland
| | - J Ruostekoski
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
| | - D S Hall
- Department of Physics and Astronomy, Amherst College, Amherst, MA, 01002-5000, USA.
| |
Collapse
|
6
|
Zhang D, Gao T, Zou P, Kong L, Li R, Shen X, Chen XL, Peng SG, Zhan M, Pu H, Jiang K. Ground-State Phase Diagram of a Spin-Orbital-Angular-Momentum Coupled Bose-Einstein Condensate. PHYSICAL REVIEW LETTERS 2019; 122:110402. [PMID: 30951335 DOI: 10.1103/physrevlett.122.110402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/28/2018] [Indexed: 06/09/2023]
Abstract
By inducing a Raman transition using a pair of Gaussian and Laguerre-Gaussian laser beams, we realize a ^{87}Rb condensate whose orbital angular momentum (OAM) and its internal spin states are coupled. By varying the detuning and the coupling strength of the Raman transition, we experimentally map out the ground-state phase diagram of the system for the first time. The transitions between different phases feature a discontinuous jump of the OAM and the spin polarization, and hence are of first order. We demonstrate the hysteresis loop associated with such first-order phase transitions. The role of interatomic interaction is also elucidated. Our work paves the way to explore exotic quantum phases in the spin-orbital-angular-momentum coupled quantum gases.
Collapse
Affiliation(s)
- Dongfang Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tianyou Gao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Peng Zou
- College of Physics, Qingdao University, Qingdao 266071, China
| | - Lingran Kong
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruizong Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Shen
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Long Chen
- Centre for Quantum and Optical Science, Swinburne University of Technology, Melbourne 3122, Australia
| | - Shi-Guo Peng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Mingsheng Zhan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Han Pu
- Department of Physics and Astronomy, and Rice Center for Quantum Materials, Rice University, Houston, Texas 77251, USA
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Kaijun Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| |
Collapse
|