Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Third boundary of the Shastry-Sutherland Model by Numerical
  Diagonalization   The Shastry-Sutherland model --- the $S=1/2$ Heisenberg antiferromagnet on
the square lattice accompanied by orthogonal dimerized interactions --- is
studied by the numerical-diagonalization method. Large-scale calculations
provide results for larger clusters that have not been reported yet. The
present study successfully captures the phase boundary between the dimer and
plaquette-singlet phases and clarifies that the spin gap increases once when
the interaction forming the square lattice is increased from the boundary. Our
calculations strongly suggest that in addition to the edge of the dimer phase
given by $J_{2}/J_{1}\sim 0.675$ and the edge of the N$\acute{\rm e}$el-ordered
phase given by $J_{2}/J_{1}\sim 0.76$, there exists a third boundary ratio
$J_{2}/J_{1}\sim 0.70$ that divides the intermediate region into two parts,
where $J_{1}$ and $J_{2}$ denote dimer and square-lattice interactions,
respectively.

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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: math
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: eess