Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonequilibrium quasiparticles and electron cooling by normal metal -
  superconductor tunnel junctions   We consider a model NISIN system with two junctions in series, where N is a
normal metal, S is a superconductor and I is an insulator. We assume that the
resistance of the first junction is high, while the resistance of the second
one is low. In this case the first junction cools the left normal electrode,
while the second junction partially removes excited quasiparticles from the
superconductor. We consider cooling properties of this double junction
structure. It is shown that the cooling power depends strongly on the ratio of
the resistances of the two junctions. In conclusion, we derive a generalized
expression for the cooling power of a NIS tunnel junction taking into account
charge imbalance effects.

9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
18
The categories of this paper are: econ
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph