Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasilocal Energy and Conserved Charges Derived from the Gravitational
  Action   The quasilocal energy of gravitational and matter fields in a spatially
bounded region is obtained by employing a Hamilton-Jacobi analysis of the
action functional. First, a surface stress-energy-momentum tensor is defined by
the functional derivative of the action with respect to the three-metric on
${}^3B$, the history of the system's boundary. Energy density, momentum
density, and spatial stress are defined by projecting the surface stress tensor
normally and tangentially to a family of spacelike two-surfaces that foliate
${}^3B$. The integral of the energy density over such a two-surface $B$ is the
quasilocal energy associated with a spacelike three-surface $\Sigma$ whose
intersection with ${}^3B$ is the boundary $B$. The resulting expression for
quasilocal energy is given in terms of the total mean curvature of the spatial
boundary $B$ as a surface embedded in $\Sigma$. The quasilocal energy is also
the value of the Hamiltonian that generates unit magnitude proper time
translations on ${}^3B$ in the direction orthogonal to $B$. Conserved charges
such as angular momentum are defined using the surface stress tensor and
Killing vector fields on ${}^3B$. For spacetimes that are asymptotically flat
in spacelike directions, the quasilocal energy and angular momentum defined
here agree with the results of Arnowitt-Deser-Misner in the limit that the
boundary tends to spatial infinity. For spherically symmetric spacetimes, it is
shown that the quasilocal energy has the correct Newtonian limit, and includes
a negative contribution due to gravitational binding.

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The categories of this paper are: solv-int
19
The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an