Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gap symmetries from the neighbor coupling in square-lattice
  superconductors   The gap symmetries of superconductivity are studied in this work. It is found
that the gap symmetries are simply determined by the 4-fold rotational
symmetries of the coupling potential on neighbor sites. A local on-site
coupling potential results in the on-site pairing with the conventional s-wave
symmetry, but a coupling potential between the nearest neighbors or the
next-nearest neighbors results in the pairing on neighbor sites with the $s^-$,
$d_{x^2-y^2}$, $d_{xy}$, or $s_{x^2y^2}$ gap symmetries. It is proved that both
isotropic and anisotropic gap functions are allowed by the 4-fold rotational
symmetries of the coupling potential. Finally a numerical computation is
performed to demonstrate the gap symmetries. This neighbor coupling provides a
unified picture for the gap functions of the conventional and the high Tc
superconductivity.

2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex