Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Numerical Study of the Spin-Flop Transition in Anisotropic Spin-1/2
  Antiferromagnets   Magnetization processes of the spin-1/2 antiferromagnetic $XXZ$ model in two
and three spatial dimensions are studied using quantum Monte Carlo method based
on stochastic series expansions. Recently developed operator-loop algorithm
enables us to show a clear evidence of the first-order phase transition in the
presence of an external magnetic field. Phase diagrams of closely related
systems, hard core bosons with nearest-neighbor repulsions, are also discussed
focusing on possibilities of phase-separated and supersolid phases.

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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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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: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an