Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unattainability of Carnot efficiency in thermal motors: Coarse-graining
  and entropy production of Feynman-Smoluchowski ratchet   We revisit and analyze the thermodynamic efficiency of the
Feynman-Smoluchowski (FS) ratchet, a classical thought experiment describing an
autonomous heat-work converter. Starting from the full kinetics of the FS
ratchet and deriving the exact forms of the hidden dissipations resulting from
coarse-graining, we restate the historical controversy over its thermodynamic
efficiency. The existence of hidden entropy productions implies that the
standard framework of stochastic thermodynamics applied to the coarse-grained
descriptions fails in capturing the dissipative feature of the system. In
response to this problem, we explore an extended framework of stochastic
thermodynamics to reconstruct the hidden entropy production from the
coarse-grained dynamics. The approach serves as a key example of how we can
systematically address the problem of thermodynamic efficiency in a
multi-variable fluctuating non-equilibrium system.

11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph