title: Mott-insulator phases of spin-3/2 fermions in the presence of quadratic Zeeman coupling.
abstract: We study the influence of the quadratic Zeeman effect on the Mott-insulator phases of hard-core 1D spin-3/2 fermions. We show that, contrary to spinor bosons, the quadratic Zeeman coupling preserves an SU(2)⊗SU(2) symmetry, leading for large-enough quadratic Zeeman coupling to an isotropic pseudo-spin-1/2 Heisenberg antiferromagnet. Decreasing the quadratic Zeeman coupling, this phase undergoes, depending on the scattering lengths, either a Kosterlitz-Thouless transition into a gapped dimerized phase or a commensurate-incommensurate transition into a gapless spin liquid. This rich phase diagram can be observed experimentally in four-component fermions in optical lattices under similar entropy constraints to those needed for Néel order in spin-1/2 gases.
authors.affiliation: Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstrasse 2 D-30167, Hannover, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Rodríguez
authors.forename: A
authors.initials: A
authors.lastname: Argüelles
authors.forename: M
authors.initials: M
authors.lastname: Colomé-Tatché
authors.forename: T
authors.initials: T
authors.lastname: Vekua
authors.forename: L
authors.initials: L
authors.lastname: Santos