Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Local Temperatures Out of Equilibrium   The temperature of a physical system is operationally defined in physics as
"that quantity which is measured by a thermometer" weakly coupled to, and at
equilibrium with the system. This definition is unique only at global
equilibrium in view of the zeroth law of thermodynamics: when the system and
the thermometer have reached equilibrium, the "thermometer degrees of freedom"
can be traced out and the temperature read by the thermometer can be uniquely
assigned to the system. Unfortunately, such a procedure cannot be
straightforwardly extended to a system out of equilibrium, where local
excitations may be spatially inhomogeneous and the zeroth law of thermodynamics
does not hold. With the advent of several experimental techniques that attempt
to extract a single parameter characterizing the degree of local excitations of
a (mesoscopic or nanoscale) system out of equilibrium, this issue is making a
strong comeback to the forefront of research. In this paper, we will review the
difficulties to define a unique temperature out of equilibrium, the majority of
definitions that have been proposed so far, and discuss both their advantages
and limitations. We will then examine a variety of experimental techniques
developed for measuring the non-equilibrium local temperatures under various
conditions. Finally we will discuss the physical implications of the notion of
local temperature, and present the practical applications of such a concept in
a variety of nanosystems out of equilibrium.

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The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph