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Mott insulating phases and quantum phase transitions of interacting spin-3/2 fermionic cold atoms in optical lattices at half filling

Hong-Hao Tu·Guang-Ming Zhang·Lu Yu
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Abstract

We study various Mott insulating phases of interacting spin-3/2 fermionic ultracold atoms in two-dimensional square optical lattices at half filling. Using a generalized one-band Hubbard model with hidden SO(5) symmetry, we identify two distinct symmetry breaking phases: the degenerate antiferromagnetic spin-dipole/spin-octupole ordering and spin-quadrupole ordering, depending on the sign of the spin-dependent interaction. These two competing orders exhibit very different symmetry properties, low energy excitations and topological characterizations. Near the SU(4) symmetric point, a quantum critical state with a $π$-flux phase may emerge due to strong quantum fluctuations, leading to spin algebraic correlations and gapless excitations.

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Hong-Hao Tu, Guang-Ming Zhang, Lu Yu. 2007-03-12. Mott insulating phases and quantum phase transitions of interacting spin-3/2 fermionic cold atoms in optical lattices at half filling. https://doi.org/10.1103/physrevb.76.014438

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