Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constitutive Relation for Nonlinear Response and Universality of
  Efficiency at Maximum Power for Tight-Coupling Heat Engines   We present a unified perspective on nonequilibrium heat engines by
generalizing nonlinear irreversible thermodynamics. For tight-coupling heat
engines, a generic constitutive relation of nonlinear response accurate up to
the quadratic order is derived from the symmetry argument and the stall
condition. By applying this generic nonlinear constitutive relation to
finite-time thermodynamics, we obtain the necessary and sufficient condition
for the universality of efficiency at maximum power, which states that a
tight-coupling heat engine takes the universal efficiency at maximum power up
to the quadratic order if and only if either the engine symmetrically interacts
with two heat reservoirs or the elementary thermal energy flowing through the
engine matches the characteristic energy of the engine. As a result, we solve
the following paradox: On the one hand, the universal quadratic term in the
efficiency at maximum power for tight-coupling heat engines proved as a
consequence of symmetry [M. Esposito, K. Lindenberg, and C. Van den Broeck,
Phys. Rev. Lett. 102, 130602 (2009); S. Q. Sheng and Z. C. Tu, Phys. Rev. E 89,
012129 (2014)]; On the other hand, two typical heat engines including the
Curzon-Ahlborn endoreversible heat engine [F. L. Curzon and B. Ahlborn, Am. J.
Phys. 43, 22 (1975)] and the Feynman ratchet [Z. C. Tu, J. Phys. A 41, 312003
(2008)] recover the universal efficiency at maximum power regardless of any
symmetry.

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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: math