Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heisenberg antiferromagnet on Cayley trees: low-energy spectrum and
  even/odd site imbalance   To understand the role of local sublattice imbalance in low-energy spectra of
s=1/2 quantum antiferromagnets, we study the s=1/2 quantum nearest neighbor
Heisenberg antiferromagnet on the coordination 3 Cayley tree. We perform
many-body calculations using an implementation of the density matrix
renormalization group (DMRG) technique for generic tree graphs. We discover
that the bond-centered Cayley tree has a quasidegenerate set of a low-lying
tower of states and an "anomalous" singlet-triplet finite-size gap scaling. For
understanding the construction of the first excited state from the many-body
ground state, we consider a wave function ansatz given by the single-mode
approximation, which yields a high overlap with the DMRG wave function.
Observing the ground-state entanglement spectrum leads us to a picture of the
low-energy degrees of freedom being "giant spins" arising out of sublattice
imbalance, which helps us analytically understand the scaling of the
finite-size spin gap. The Schwinger-boson mean-field theory has been
generalized to nonuniform lattices, and ground states have been found which are
spatially inhomogeneous in the mean-field parameters.

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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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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: dg-ga
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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: eess
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg