Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phonon dispersion and the competition between pairing and charge order   The Holstein Model (HM) describes the interaction between fermions and a
collection of local (dispersionless) phonon modes. In the dilute limit, the
phonon degrees of freedom dress the fermions, giving rise to polaron and
bipolaron formation. At higher densities, the phonons mediate collective
superconducting (SC) and charge density wave (CDW) phases. Quantum Monte Carlo
(QMC) simulations have considered both these limits, but have not yet focused
on the physics of more general phonon spectra. Here we report QMC studies of
the role of phonon dispersion on SC and CDW order in such models. We quantify
the effect of finite phonon bandwidth and curvature on the critical temperature
$T_{\rm cdw}$ for CDW order, and also uncover several novel features of
diagonal long range order in the phase diagram, including a competition between
charge patterns at momenta ${\bf q}=(\pi,\pi)$ and ${\bf q}=(0,\pi)$ which
lends insight into the relationship between Fermi surface nesting and the
wavevector at which charge order occurs. We also demonstrate SC order at
half-filling in situations where nonzero bandwidth sufficiently suppresses
  $T_{\rm cdw}$.

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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: q-bio
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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: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn