Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pristine Mott Insulator from an Exactly Solvable Spin-1/2 Kitaev Model   We propose an exactly solvable quantum spin-1/2 model with time reversal
invariance on a two dimensional brick-wall lattice, where each unit cell
consists of three sites. We find that the ground states are algebraic quantum
spin liquid states. The spinon excitations are gapless and the energy
dispersion is linear around two Dirac points. The ground states are of
three-fold topological degeneracy on a torus. Breaking the time reversal
symmetry opens a bulk energy gap and the $Z_2$ vortices obey non-Abelian
statistics.

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The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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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: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph