Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase structure of monolayer graphene from effective U(1) gauge theory
  on honeycomb lattice   Phase structure of monolayer graphene is studied on the basis of a U(1) gauge
theory defined on the honeycomb lattice. Motivated by the strong coupling
expansion of U(1) lattice gauge theory, we consider on-site and
nearest-neighbor interactions between the fermions. When the on-site
interaction is dominant, the sublattice symmetry breaking (SLSB) of the
honeycomb lattice takes place. On the other hand, when the interaction between
nearest neighboring sites is relatively strong, there appears two different
types of spontaneous Kekule distortion (KD1 and KD2), without breaking the
sublattice symmetry. The phase diagram and phase boundaries separating SLSB,
KD1 and KD2 are obtained from the mean-field free energy of the effective
fermion model. A finite gap in the spectrum of the electrons can be induced in
any of the three phases.

19
The categories of this paper are: eess
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The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
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The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph