1. School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China 2. Department of Applied Physics, South China Agricultural University, Guangzhou 510642, China
We study the spontaneous symmetry breaking of dipolar Bose–Einstein condensates trapped in stacks of two-well systems, which may be effectively built as one-dimensional trapping lattices sliced by a repelling laser sheet. If the potential wells are sufficiently deep, the system is modeled by coupled discrete Gross–Pitaevskii equations with nonlocal self- and cross-interaction terms representing dipole–dipole interactions. When the dipoles are not polarized perpendicular or parallel to the lattice, the crossinteraction is asymmetric, replacing the familiar symmetric two-component solitons with a new species of cross-symmetric or-asymmetric ones. The orientation of the dipole moments and the interwell hopping rate strongly affect the shapes of the discrete two-component solitons as well as the characteristics of the cross-symmetry breaking and the associated phase transition. The sub- and super-critical types of cross-symmetry breaking can be controlled by either the hopping rate between the components or the total norm of the solitons. The effect of the interplay between the contact nonlinearity and the dipole angle on the cross-symmetry breaking is also discussed.
Y.Li, J.Liu, W.Pang, and B. A.Malomed, Matterwave solitons supported by field-induced dipole–dipole repulsion with spatially modulated strength, Phys. Rev. A88(5), 053630(2013) https://doi.org/10.1103/PhysRevA.88.053630
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T.Lahaye, T.Koch, B.Fröhlich, M.Fattori, J.Metz, A.Griesmaier, S.Giovanazzi, and T.Pfau, Strong dipolar effects in a quantum ferrofluid, Nature448(7154), 672(2007) https://doi.org/10.1038/nature06036
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H.Saito, Y.Kawaguchi, and M.Ueda, Ferrofluidity in a two-component dipolar Bose–Einstein condensate, Phys. Rev. Lett. 102(23), 230403(2009) https://doi.org/10.1103/PhysRevLett.102.230403
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H.Kadau, M.Schmitt, M.Wenzel, C.Wink, T.Maier, I.Ferrier-Barbut, and T.Pfau, Observing the Rosensweig instability of a quantum ferrofluid, Nature530(7589), 194(2016) https://doi.org/10.1038/nature16485
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M.Klawunn, R.Nath, P.Pedri, andL.Santos, Transverse instability of straight vortex lines in dipolar Bose– Einstein condensates, Phys. Rev. Lett. 100(24), 240403(2008) https://doi.org/10.1103/PhysRevLett.100.240403
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A.Maluckov, G.Gligoric, Lj.Hadžievski, B. A.Malomed, and T.Pfau, Stable periodic density waves in dipolar Bose–Einstein condensates trapped in optical lattices, Phys. Rev. Lett. 108(14), 140402(2012) https://doi.org/10.1103/PhysRevLett.108.140402
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J.Cuevas, B. A.Malomed, P. G.Kevrekidis, and D. J.Frantzeskakis, Solitons in quasi-one-dimensional Bose– Einstein condensates with competing dipolar and local interactions, Phys. Rev. A79(5), 053608(2009) https://doi.org/10.1103/PhysRevA.79.053608
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J.Huang, X.Jiang, H.Chen, Z.Fan, W.Pang, and Y.Li, Quadrupolar matter-wave soliton in two-dimensional free space, Front. Phys. 10(4), 100507(2015) https://doi.org/10.1007/s11467-015-0501-1
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R.Nath, P.Pedri, and L.Santos, Stability of dark solitons in three dimensional dipolar Bose–Einstein condensates, Phys. Rev. Lett. 101(21), 210402(2008) https://doi.org/10.1103/PhysRevLett.101.210402
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T.Bland, M. J.Edmonds, N. P.Proukakis, A. M.Martin, D. H. J.O’Dell, and N. G.Parker, Controllable nonlocal interactions between dark solitons in dipolar condensates, Phys. Rev. A92(6), 063601(2015) https://doi.org/10.1103/PhysRevA.92.063601
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G.Gligorić, A.Maluckov, L.Hadžievski, and B. A.Malomed, Bright solitons in the one-dimensional discrete Gross–Pitaevskii equation with dipole–dipole interactions, Phys. Rev. A78(6), 063615(2008) https://doi.org/10.1103/PhysRevA.78.063615
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G.Gligorić, A.Maluckov, M.Stepič L.Hadžievski, and B. A.Malomed, Two-dimensional discrete solitons in dipolar Bose–Einstein condensates, Phys. Rev. A81(1), 013633(2010) https://doi.org/10.1103/PhysRevA.81.013633
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H.Chen, Y.Liu, Q.Zhang, Y.Shi, W.Pang, and Y.Li, Dipolar matter-wave solitons in two-dimensional anisotropic discrete lattices, Phys. Rev. A93(5), 053608(2016) https://doi.org/10.1103/PhysRevA.93.053608
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Y.Xu, Y.Zhang, and C.Zhang, Bright solitons in a twodimensional spin–orbit-coupled dipolar Bose–Einstein condensate, Phys. Rev. A92(1), 013633(2015) https://doi.org/10.1103/PhysRevA.92.013633
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X.Jiang, Z.Fan, Z.Chen, W.Pang, Y.Li, and B. A.Malomed, Two-dimensional solitons in dipolar Bose– Einstein condensates with spin–orbit-coupling, Phys. Rev. A93(2), 023633(2016) https://doi.org/10.1103/PhysRevA.93.023633
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Y.Li, Y.Liu, Z.Fan, W.Pang, S.Fu, and B. A.Malomed, Two-dimensional dipolar gap solitons in free space with spin–orbit coupling, Phys. Rev. A95(6), 063613(2017) https://doi.org/10.1103/PhysRevA.95.063613
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