Ferromagnetism in a two-component Bose-Hubbard model with synthetic spin-orbit coupling

Abstract

We study the effect of the synthetic spin-orbit coupling in a two-component Bose-Hubbard model in one dimension by employing the density-matrix renormalization group method. A ferromagnetic long-range order emerges in both Mott insulator and superfluid phases resulting from the spontaneous breaking of the Z2 symmetry, when the spin-orbit coupling term becomes comparable to the hopping kinetic energy and the intercomponent interaction is smaller than the intracomponent as well. This effect is expected to be detectable with the present realization of the synthetic spin-orbit coupling in experiments.

Quantum magnetism of bosons with synthetic gauge fields in one-dimensional optical lattices: A density-matrix renormalization-group study

“…By suitably coupling the atoms to laser fields, experimentalists have successfully created both Abelian (effective magnetic fields [4,5]) and non-Abelian gauge potentials (effective spin-orbit coupling [6]) in ultracold atomic systems, where the neutral atoms subjected to synthetic gauge fields exhibit a variety of interesting phenomena, including the Hofstadter fractal spectrum [7][8][9], spin-orbit coupled BoseEinstein condensates [6,[10][11][12][13][14][15][16][17], as well as spin-orbit coupled degenerate Fermi gases [18][19][20]. While most of these studies focus on the weakly interacting regime, the addition of a tunable optical lattice enables us to investigate the strongly correlated Mott insulating phases in the presence of gauge fields, where the interplay between strong interactions and synthetic gauge fields can give rise to exotic quantum magnetism that is difficult to access in solid-state physics [21][22][23][24][25][26][27][28][29][30].…”

Properties of spin–orbit-coupled Bose–Einstein condensates

“…The most famous example of this is the existence of a stripe phase that is an equal superposition of two minima in momentum space [40]. The ground state and collective excitations of SOC BECs have been investigated for a large number of different settings, such as homogeneous [40][41][42][43][44][45][46][47][48][49], harmonic [50][51][52][53][54], in the presence of a periodic optical lattice [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72], a double-well [73][74][75], rotation [76][77][78][79][80][81], inside an optical cavity [82][83][84][85][86], and for particles with dipolar interaction …”

Thermodynamics of a spin-12XYZ Heisenberg chain with a Dzyaloshinskii-Moriya interaction

“…Recently, a synthetic spin-orbit coupling (SOC), or equivalently, gauge field, was successfully realized in experiments and a variety of phases as well as phase transitions were observed [15][16][17][18] . These experiments have spurred great interest in studying the artificial SOC as well as gauge field in ultracold systems [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . In the deep insulating region, such an SOC can be approximated 21,26 by the Dzyaloshinskii-Moriya (DM) interaction 35,36 .…”

“…The Hamiltonian (2), or equivalently Hamiltonian (1) at unit filling in the strong coupling limit, has been studied by several groups using density-matrix renormalization group (DMRG) method in combination with some analytic methods [25][26][27][28][29] . For U ′ = U , the DM interaction can be eliminated by a site-dependent rotation of the spin operators, resulting in an isotropic Heisenberg chain with FM coupling 20 .…”