Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dimer-Monomer Ground State for Extended Spin-1/2 Diamond Chain   We present a condition in which the dimer-monomer state is exactly the ground
state of an extended diamond chain with spin magnitude 1/2. The Hamiltonian of
the extended diamond chain includes next-nearest-neighbor exchange interactions
and distortions, where the spin magnitude of the spin pair on a singlet dimer
is not generally conserved. The method of deriving the condition is based on
representing the Hamiltonian in a complete square form. The dimer-monomer
ground state is found even if the Hamiltonian has no space-reflection
symmetries.

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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga