Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Gravitational-Electromagnetic Analogy: A Possible Solution to the
  Vacuum-Energy and Dark-Energy Problems   There is a set of first-order differential equations for the curvature tensor
in general relativity (the curvature equations or CEs for short) that are
strikingly similar to the Maxwell equations of electrodynamics. This paper
considers whether Mother Nature may have used the same basic pattern for her
laws of gravitation and electrodynamics, in which case the CEs might be viewed
as the field equations of gravitation in place of Einstein's equation. This is
not a new theory of gravitation (because the curvature equations are derivable
from Einstein's equation), but rather is a mild reinterpretation of general
relativity that solves the vacuum-energy problem and the dark-energy problem of
cosmology. The results of this paper allow one to understand how the effective
energy density of the observed cosmological constant can be so vastly smaller
than estimates of the vacuum energy of quantum fields and why the vacuum energy
of quantum fields does not contribute as a source of curvature.

18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg