Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement Entropy in an Antiferromagnetic Heisenberg Spin Chain with
  Boundary Impurities   The effects of boundary impurities on the entanglement entropy in an
antiferromagnetic Heisenberg opened spin-$1/2$ chain are investigated. The
method of density-matrix renormalization-group is used to obtain the bipartite
entanglement. The entropy increases when the length of the subsystem increases.
It will approach to a constant when system length is very large. With the same
impurity interaction, qutrit impurities of spin-$1$ can increase the
entanglement entropy.

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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol