Strong-coupling phases of the spin-orbit-coupled spin-1 Bose-Hubbard chain: Odd-integer Mott lobes and helical magnetic phases
J. H. Pixley, William S. Cole, Ian B. Spielman +2 more
We study the odd-integer filled Mott phases of a spin-1 Bose-Hubbard chain and determine their fate in the presence of a Raman induced spin-orbit coupling which has been achieved in ultracold atomic gases; this system is described by a quantum spin-1 chain with a spiral magnetic field. The spiral magnetic field initially induces helical order with either ferromagnetic or dimer order parameters, giving rise to a spiral paramagnet at large field. The spiral ferromagnet-to-paramagnet phase transition is in a universality class with critical exponents associated with the divergence of the correlation length $\ensuremath{\nu}\ensuremath{\approx}2/3$ and the order-parameter susceptibility $\ensuremath{\gamma}\ensuremath{\approx}1/2$. We solve the effective spin model exactly using the density-matrix renormalization group, and compare with both a large-$S$ classical solution and a phenomenological Landau theory. We discuss how these exotic bosonic magnetic phases can be produced and probed in ultracold atomic experiments in optical lattices.
arXiv:1705.06742•Physical Review A•Oct 23, 2017•12 citations