Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Minimisation of a Free-Energy-Like Potential for Non-Equilibrium Systems
  at Steady State   This study examines a new formulation of non-equilibrium thermodynamics,
which gives a conditional derivation of the ``maximum entropy production''
(MEP) principle for flow and/or chemical reaction systems at steady state. The
analysis uses a dimensionless potential function $\phi_{st}$ for
non-equilibrium systems, analogous to the free energy concept of equilibrium
thermodynamics. Spontaneous reductions in $\phi_{st}$ arise from increases in
the ``flux entropy'' of the system - a measure of the variability of the fluxes
- or in the local entropy production; conditionally, depending on the behaviour
of the flux entropy, the formulation reduces to the MEP principle. The inferred
steady state is also shown to exhibit high variability in its instantaneous
fluxes and rates, consistent with the observed behaviour of turbulent fluid
flow, heat convection and biological systems; one consequence is the
coexistence of energy producers and consumers in ecological systems. The
different paths for attaining steady state are also classified.

1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin