Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tunneling Gap as Evidence for Time-Reversal Symmetry Breaking at
  Surfaces of High-Temperature Superconductors   It is argued that recent Josephson junction and point-contact tunneling
experiments, interpreted as intended by their authors, indicate that
time-reversal symmetry breaking occurs at surfaces of cuprate superconductors.
The variation among experiments and the failure of previous searches to find
$T$-violation are ascribed to disorder and effects of 3-dimensionality. The
``anyon" approach to the $t$-$J$ model is shown to predict a conventional BCS
order parameter of $d_{x^2-y^2} + i \epsilon \ d_{xy}$ symmetry, with $\epsilon
$ roughly 3 times the doping fraction $\delta $, which is consistent with these
experiments but not demonstrated by them.

36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph