Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bond excitations in the pseudogap phase of the Hubbard Model   Using the dynamical cluster approximation, we calculate the correlation
functions associated with the nearest neighbor bond operator which measure the
z component of the spin exchange in the two-dimensional Hubbard model with $U$
equal to the bandwidth. We find that in the pseudogap region, the local bond
susceptibility diverges at T=0. This shows the existence of degenerate bond
spin excitation and implies quantum criticality and bond order formation when
long range correlations are considered. The strong correlation between
excitations on parallel neighboring bonds suggests bond singlet dimerization.
The suppression of divergence for $n< \approx 0.78$ implies that tor these
model parameters this is quantum critical point which separates the
unconventional pseudogap region characterized by bond order from a conventional
Fermi liquid.

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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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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: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: physics
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The categories of this paper are: adap-org