Title | Chiral magnetism and spontaneous spin Hall effect of interacting Bose superfluids |
Publication Type | Journal Article |
Year of Publication | 2014 |
Authors | X. Li, S. S. Natu, A. Paramekanti, and S. Das Sarma |
Journal | Nature Communications |
Volume | 5 |
Date Published | 10/2014 |
Keywords | chiral magnetism, Spin-orbit coupling |
Abstract | Recent experiments on ultracold atoms in optical lattices have synthesized a variety of tunable bands with degenerate double-well structures in momentum space. Such degeneracies in the single-particle spectrum strongly enhance quantum fluctuations, and often lead to exotic many-body ground states. Here we consider weakly interacting spinor Bose gases in such bands, and discover a universal quantum ‘order by disorder’ phenomenon which selects a novel superfluid with chiral spin order displaying remarkable properties such as spontaneous spin Hall effect and momentum space antiferromagnetism. For bosons in the excited Dirac band of a hexagonal lattice, such a state supports staggered spin loop currents in real space. We show that Bloch oscillations provide a powerful dynamical route to quantum state preparation of such a chiral spin superfluid. Our predictions can be readily tested in spin-resolved time-of-flight experiments. |
URL | http://www.nature.com/ncomms/2014/141010/ncomms6174/full/ncomms6174.html |
DOI | 10.1038/ncomms6174 |