Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasilocal energy and thermodynamic equilibrium conditions   Equilibrium thermodynamic laws are typically applied to horizons in general
relativity without stating the conditions that bring them into equilibrium. We
fill this gap by applying a new thermodynamic interpretation to a generalized
Raychaudhuri equation for a worldsheet orthogonal to a closed spacelike
2-surface, the "screen", which encompasses a system of arbitrary size in
nonequilibrium with its surroundings in general. In the case of spherical
symmetry this enables us to identify quasilocal thermodynamic potentials
directly related to standard quasilocal energy definitions. Quasilocal
thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature
of the screen. Moreover, without any direct reference to surface gravity, we
find that the system comes into quasilocal thermodynamic equilibrium when the
screen is located at a generalized apparent horizon. Examples of the
Schwarzschild, Friedmann-Lema\^itre and Lema\^itre-Tolman geometries are
investigated and compared. Conditions for the quasilocal thermodynamic and
hydrodynamic equilibrium states to coincide are also discussed, and a
quasilocal virial relation is suggested as a potential application of this
approach.

16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin