Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Feeding upon negative entropy in a thermal-equilibrium environment   The validity of the Second Law of thermodynamics, indisputable in the
macroscopic world, is challenged at the mesoscopic level: a mesoscopic isolated
system, possessing spatial dimensions of the order of a few microns, is
capable, as shown by a straightforward kinetic analysis, to exhibit a perpetuum
mobile behavior associated with large negative variations of the Clausius
entropy of the system. This violation of the Second Law is expedient for
devising a cyclic process through which an isolated system can extract energy
from a surrounding thermal bath.

32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph