Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entropic anomaly and maximal efficiency of microscopic heat engines   The efficiency of microscopic heat engines in a thermally heterogenous
environment is considered. We show that, as a consequence of the recently
discovered entropic anomaly, quasi-static engines, whose efficiency is maximal
in a fluid at uniform temperature, have in fact vanishing efficiency in
presence of temperature gradients. For slow cycles the efficiency falls off as
the inverse of the period. The maximum efficiency is reached at a finite value
of the cycle period that is inversely proportional to the square root of the
gradient intensity. The relative loss in maximal efficiency with respect to the
thermally homogeneous case grows as the square root of the gradient. As an
illustration of these general results, we construct an explicit, analytically
solvable example of a Carnot stochastic engine. In this thought experiment, a
Brownian particle is confined by a harmonic trap and immersed in a fluid with a
linear temperature profile. This example may serve as a template for the design
of real experiments in which the effect of the entropic anomaly can be
measured.

29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
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
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph