Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear thermoelectricity in point-contacts at pinch-off: a
  catastrophe aids cooling   We consider refrigeration and heat engine circuits based on the nonlinear
thermoelectric response of point-contacts at pinch-off, allowing for
electrostatic interaction effects. We show that a refrigerator can cool to much
lower temperatures than predicted by the thermoelectric figure-of-merit ZT
(which is based on linear-response arguments). The lowest achievable
temperature has a discontinuity, called a fold catastrophe in mathematics, at a
critical driving current I=I_c. For I >I_c one can in principle cool to
absolute zero, when for I<I_c the lowest temperature is about half the ambient
temperature. Heat back-flow due to phonons and photons stop cooling at a
temperature above absolute zero, and above a certain threshold turns the
discontinuity into a sharp cusp. We also give a heuristic condition for when an
arbitrary system's nonlinear response means that its ZT ceases to indicate
(even qualitatively) the lowest temperature to which the system can
refrigerate.

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The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph