Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Topological and nematic superconductivity mediated by ferro-SU(4)
  fluctuations in twisted bilayer graphene   We propose an SU(4) spin-valley-fermion model to investigate the
superconducting instabilities of twisted bilayer graphene (TBG). In this
approach, bosonic fluctuations associated with an emergent SU(4) symmetry,
corresponding to combined rotations in valley and spin spaces, couple to the
low-energy fermions that comprise the flat bands. These fluctuations are peaked
at zero wave-vector, reflecting the "ferromagnetic-like" SU(4) ground state
recently found in strong-coupling solutions of microscopic models for TBG.
Focusing on electronic states related to symmetry-imposed points of the Fermi
surface, dubbed here "valley hot-spots" and "van Hove hot-spots", we find that
the coupling to the itinerant electrons partially lifts the huge degeneracy of
the ferro-SU(4) ground state manifold, favoring inter-valley order, spin-valley
coupled order, ferromagnetic order, spin-current order, and valley-polarized
order, depending on details of the band structure. These fluctuations, in turn,
promote attractive pairing interactions in a variety of closely competing
channels, including a nodeless $f$-wave state, a nodal $i$-wave state, and
topological $d+id$ and $p+ip$ states with unusual Chern numbers $2$ and $4$,
respectively. Nematic superconductivity, although not realized as a primary
instability of the system, still appears as a consequence of the
near-degeneracy of superconducting order parameters that transform as
one-dimensional and two-dimensional irreducible representations of the point
group $D_{6}$.

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The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
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The categories of this paper are: eess
16
The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg