Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Plaquette Ground State in the Two-dimensional SU(4) Spin-Orbital Model   In order to understand the properties of Mott insulators with strong ground
state orbital fluctuations, we study the zero temperature properties of the
SU(4) spin-orbital model on a square lattice. Exact diagonalizations of finite
clusters suggest that the ground state is disordered with a singlet-multiplet
gap and possibly low-lying SU(4) singlets in the gap. An interpretation in
terms of plaquette SU(4) singlets is proposed. The implications for LiNiO_2 are
discussed.

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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: econ