Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Note on possibility of proximity induced spontaneous currents in
  superconductor/normal metal heterostructures   We analyse the possibility of the appearance of spontaneous currents in
proximated superconducting/normal metal (S/N) heterostructure when Cooper pairs
penetrate into the normal metal from the superconductor. In particular, we
calculate the free energy of the S/N structure. We show that whereas the free
energy of the N film $F_{N}$ in the presence of the proximity effect increases
compared to the normal state, the total free energy, which includes the
boundary term $F_{B}$, decreases. The condensate current decreases $F_{N}$, but
increases the total free energy making the current-carrying state of the S/N
system energetically unfavorable.

13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
18
The categories of this paper are: econ
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex