Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Effect of Magnetic Impurities on Superfluid $^3$He in Aerogel   The critical field for superfluid $^3$He in axially compressed, anisotropic
silica aerogel is shown to be the result of an anisotropic distribution of
magnetic impurities affecting the superfluid $A$ phase. The critical field
results from the fact that the $A$ phase is suppressed relative to the $B$
phase which is immune to the effects of magnetic impurities. In the absence of
magnetic quasiparticle scattering in anisotropic aerogel, we find that the
relative symmetry of $A$ and $B$ phase order parameters is the same as in
isotropic aerogel, just as it is in pure superfluid $^3$He. These results are
of potential importance for understanding unconventional superconductivity.

33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio