Atomic,Molecular, and Optical Physics

Bose-Einstein condensates in spin-twisted optical lattices

  • Meiling WANG ,
  • Chengyi ZUO ,
  • Yan LI
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  • School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China

Received date: 2023-04-11

  Online published: 2024-05-25

Abstract

The characteristics of the ground states of Bose-Einstein condensates (BEC) in spin-dependent bilayer square optical lattices are investigated in this paper. The relative twist angle between the two lattices and the interlayer coupling strength are the main tunable parameters that affect the density distribution of the ultracold atoms. When the lowest band of the lattices exhibits a single-well dispersion, the localization of the ultracold atoms in the Moiré lattice can be determined from the twist angle, interlayer coupling strength, number of atoms, and lattice depth. When the lowest band of the lattices exhibits a double-well dispersion, the twist between the lattices leads to the twist of the two spin states. With an increase in interlayer coupling strength, the two twisted spin states will overlap. The results of this work will stimulate further exploration of novel quantum effect with ultracold atoms in twisted optical lattices.

Cite this article

Meiling WANG , Chengyi ZUO , Yan LI . Bose-Einstein condensates in spin-twisted optical lattices[J]. Journal of East China Normal University(Natural Science), 2024 , 2024(3) : 64 -72 . DOI: 10.3969/j.issn.1000-5641.2024.03.007

References

1 ANDREI E Y, MACDONALD A H.. Graphene bilayers with a twist. Nature Materials, 2020, 19 (12): 1265- 1275.
2 BALENTS L, DEAN C R, EFETOV D K, et al.. Superconductivity and strong correlations in Moiré flat bands. Nature Physics, 2020, 16 (7): 725- 733.
3 CAO Y, FATEMI V, DEMIR A, et al.. Correlated insulator behaviour at half-filling in magic-angle graphene superlattices. Nature, 2018, 556 (7699): 80- 84.
4 CAO Y, FATEMI V, FANG S, et al.. Unconventional superconductivity in magic-angle graphene superlattices. Nature, 2018, 556 (7699): 43- 50.
5 KENNES D M, CLAASSEN M, XIAN L, et al.. Moiré heterostructures as a condensed-matter quantum simulator. Nature Physics, 2021, 17 (2): 155- 163.
6 LU X B, STEPANOV P, YANG W, et al.. Superconductors, orbital magnets and correlated states in magic-angle bilayer graphene. Nature, 2019, 574 (7780): 653- 657.
7 YANKOWITZ M, CHEN S W, POLSHYN H, et al.. Tuning superconductivity in twisted bilayer graphene. Science, 2019, 363 (6431): 1059- 1064.
8 LOPES DOS SANTOS J M B, PERES N M R, CASTRO NETO A H.. Graphene bilayer with a twist: Electronic structure. Physical Review Letters, 2007, 99 (25): 256802.
9 MELE E J.. Commensuration and interlayer coherence in twisted bilayer graphene. Physical Review B, 2010, 81 (16): 161405.
10 MOON P, KOSHINO M.. Energy spectrum and quantum Hall effect in twisted bilayer graphene. Physical Review B, 2012, 85 (19): 195458.
11 TARNOPOLSKY G, KRUCHKOV A J, VISHWANATH A.. Origin of magic angles in twisted bilayer graphene. Physical Review Letters, 2019, 122 (10): 106405.
12 SOLTAN-PANAHI P, STRUCK J, HAUKE P, et al.. Multi-component quantum gases in spin-dependent hexagonal lattices. Nature Physics, 2011, 7 (5): 434- 440.
13 WIRTH G, ?LSCHL?GER M, HEMMERICH A.. Evidence for orbital superfluidity in the P-band of a bipartite optical square lattice. Nature Physics, 2011, 7 (2): 147- 153.
14 TARRUELL L, GREIF D, UEHLINGER T, et al.. Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice. Nature, 2012, 483 (7389): 302- 305.
15 JO G B, GUZMAN J, THOMAS C K, et al.. Ultracold atoms in a tunable optical kagome lattice. Physical Review Letters, 2012, 108 (4): 045305.
16 GONZáLEZ-TUDELA A, CIRAC J I.. Cold atoms in twisted-bilayer optical potentials. Physical Review A, 2019, 100 (5): 053604.
17 LUO X W, ZHANG C W.. Spin-twisted optical lattices: Tunable flat bands and Larkin-Ovchinnikov superfluids. Physical Review Letters, 2021, 126 (10): 103201.
18 MENG Z M, WANG L W, HAN W, et al.. Atomic Bose–Einstein condensate in twisted-bilayer optical lattices. Nature, 2023, 615 (7951): 231- 236.
19 SALAMON T, CELI A, CHHAJLANY R W, et al.. Simulating twistronics without a twist. Physical Review Letters, 2020, 125 (3): 030504.
20 GRA? T, CHHAJLANY R W, TARRUELL L, et al.. Proximity effects in cold atom artificial graphene. 2D Materials, 2017, 4 (1): 015039.
21 BLOCH I, DALIBARD J, ZWERGER W.. Many-body physics with ultracold gases. Reviews of Modern Physics, 2008, 80 (3): 885- 964.
22 POSAZHENNIKOVA A.. Colloquium: Weakly interacting, dilute Bose gases in 2D. Reviews of Modern Physics, 2006, 78 (4): 1111- 1134.
23 PAPP S B, PINO J M, WIEMAN C E.. Tunable miscibility in a dual-species Bose-Einstein condensate. Physical Review Letters, 2008, 101 (4): 040402.
24 WANG P, ZHENG Y L, CHEN X F, et al.. Localization and delocalization of light in photonic Moiré lattices. Nature, 2020, 577 (7788): 42- 46.
25 DOMíNGUEZ-CASTRO G A, PAREDES R.. The Aubry–André model as a hobbyhorse for understanding the localization phenomenon. European Journal of Physics, 2019, 40 (4): 045403.
26 YAO H P, KHOUDLI A, BRESQUE L, et al.. Critical behavior and fractality in shallow one-dimensional quasiperiodic potentials. Physical Review Letters, 2019, 123 (7): 070405.
27 MUKHERJEE S, SPRACKLEN A, CHOUDHURY D, et al.. Modulation-assisted tunneling in laser-fabricated photonic Wannier–Stark ladders. New Journal of Physics, 2015, 17 (11): 115002.
28 LI X, LI X P, DAS SARMA S.. Mobility edges in one-dimensional bichromatic incommensurate potentials. Physical Review B, 2017, 96 (8): 085119.
29 KHAMEHCHI M A, QU C L, MOSSMAN M E, et al.. Spin-momentum coupled Bose-Einstein condensates with lattice band pseudospins. Nature Communications, 2016, 7 (1): 10867.
30 PARKER C V, HA L C, CHIN C.. Direct observation of effective ferromagnetic domains of cold atoms in a shaken optical lattice. Nature Physics, 2013, 9 (12): 769- 774.
31 LIU T T, CLARK L W, CHIN C.. Exotic domain walls in Bose-Einstein condensates with double-well dispersion. Physical Review A, 2016, 94 (6): 063646.
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