Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Robust $s\pm$ Superconductivity in a Two-Band Hubbard-Fr{\"o}hlich Model
  of Alkali Doped Organics   The damaging effect of strong electron-electron repulsion on regular,
electron-phonon %$s$-wave superconductivity is a standard tenet. In spite of
that, an increasing number of compounds such as fullerides and more recently
alkali-doped aromatics exhibit %$s$-wave or presumably $s$ wave
superconductivity despite very narrow bands and very strong electron repulsion.
Here, we explore superconducting solutions of a model Hamiltonian inspired by
the electronic structure of alkali doped aromatics. The model is a two-site,
two-narrow-band metal with a single intersite phonon, leading to
attraction-mediated, two-order parameter superconductivity. On top of that, the
model includes a repulsive on-site Hubbard $U$, whose effect on the
superconductivity we study. Starting within mean field, we find that $s \pm$
superconductivity is the best solution surviving the presence of $U$, whose
effect is canceled out by the opposite signs of the two order parameters. The
correlated Gutzwiller study that follows is necessary because without electron
correlations the superconducting state would in this model be superseded by an
antiferromagnetic insulating state with lower energy. The Gutzwiller
correlations lower the energy of the metallic state, with the consequence that
the $s \pm$ superconducting state is stabilized and even strengthened for small
Hubbard $U$.

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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph