Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Brownian refrigeration by hybrid tunnel junctions   Voltage fluctuations generated in a hot resistor can cause extraction of heat
from a colder normal metal electrode of a hybrid tunnel junction between a
normal metal and a superconductor. We extend the analysis presented in [Phys.
Rev. Lett. 98, 210604 (2007)] of this heat rectifying system, bearing
resemblance to a Maxwell's demon. Explicit analytic calculations show that the
entropy of the total system is always increasing. We then consider a single
electron transistor configuration with two hybrid junctions in series, and show
how the cooling is influenced by charging effects. We analyze also the cooling
effect from nonequilibrium fluctuations instead of thermal noise, focusing on
the shot noise generated in another tunnel junction. We conclude by discussing
limitations for an experimental observation of the effect.

9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th