title: Uniaxial and biaxial spin nematic phases induced by quantum fluctuations.
abstract: It is shown that zero point quantum fluctuations completely lift the accidental continuous degeneracy that is found in mean field analysis of quantum spin nematic phases of hyperfine spin-2 cold atoms. The result is two distinct ground states which have higher symmetries: a uniaxial spin nematic and a biaxial spin nematic with dihedral symmetry Dih4. There is a novel first-order quantum phase transition between the two phases as atomic scattering lengths are varied. We find that the ground state of 87Rb atoms should be a uniaxial spin nematic. We note that the energy barrier between the phases could be observable in dynamical experiments.
authors.affiliation: Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC, Canada V6T1Z1.
authors.forename: Jun Liang
authors.initials: JL
authors.lastname: Song
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Semenoff
authors.forename: Fei
authors.initials: F
authors.lastname: Zhou