Mott-insulator phases of spin-3/2 fermions in the presence of quadratic Zeeman coupling.
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.
Rodríguez
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K
Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstrasse 2 D-30167, Hannover, Germany.
Argüelles
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A
Colomé-Tatché
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M
Vekua
T
T
Santos
L
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