Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic anisotropy effects on quantum impurities in superconducting
  host   We study the magnetic anisotropy effects on the localized sub-gap excitations
induced by quantum impurities coupled to a superconducting host. We establish
the ground-state phase diagrams for single-channel and two-channel high-spin
Kondo impurities; they unveil surprising complexity that results from the
(multi-stage) Kondo screening in competition with the superconducting
correlations and the magnetic anisotropy splitting of the spin multiplets. We
discuss the possibility of detecting the Zeeman splitting of the sub-gap
states, which would provide an interesting spectroscopic tool for studying the
magnetism on the single-atom level. We also study the problem of two impurities
coupled by the Heisenberg exchange interaction, and we follow the evolution of
the sub-gap states for both antiferromagnetic and ferromagnetic coupling. For
sufficiently strong antiferromagnetic coupling, the impurities bind into a
singlet state that is non-magnetic, thus the sub-gap states move to the edge of
the gap and can no longer be discerned. For ferromagnetic coupling, some
excited states remain present inside the gap.

17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics