Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Parity Violation in a Single Domain of Spin-Triplet Sr2RuO4
  Superconductors   We observed an unconventional parity-violating vortex in single domain
Sr2RuO4 single crystals using a transport measurement. The current-voltage
characteristics of submicron Sr2RuO4 shows that the induced voltage has
anomalous components which are even function of the bias current. The results
may suggest that the vortex itself has a helical internal structure
characterized by a Hopf invariant (a topological invariant). We also discuss
that the hydrodynamics of such a helical vortex causes the parity violation to
retain the topological invariant.

2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas