Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The anisotropic coupling of gravity and electromagnetism in
  Ho\v{r}ava-Lifshitz theory   We analyze the electromagnetic-gravity interaction in a pure
Ho\v{r}ava-Lifshitz framework. To do so we formulate the Ho\v{r}ava-Lifshitz
gravity in $4+1$ dimensions and perform a Kaluza-Klein reduction to $3+1$
dimensions. We use this reduction as a mathematical procedure to obtain the
$3+1$ coupled theory, which at the end is considered as a fundamental,
self-consistent, theory. The critical value of the dimensionless coupling
constant in the kinetic term of the action is $\lambda=1/4$. It is the kinetic
conformal point for the non-relativistic electromagnetic-gravity interaction.
In distinction, the corresponding kinetic conformal value for pure
Ho\v{r}ava-Lifshitz gravity in $3+1$ dimensions is $\lambda=1/3$. We analyze
the geometrical structure of the critical and noncritical cases, they
correspond to different theories. The physical degrees of freedom propagated by
the noncritical theory are the transverse traceless graviton, the transverse
gauge vector and two scalar fields. In the critical theory one of the scalars
is absent, only the dilaton scalar field is present. The gravity and vector
excitations propagate with the same speed, which at low energy can be taken to
be the speed of light. The field equations for the gauge vector in the
non-relativistic theory have exactly the same form as the relativistic
electromagnetic field equations arising from the Kaluza-Klein reduction of
General Relativity, and are equal to them for a particular value of one of the
coupling constants. The potential in the Hamiltonian is a polynomial of finite
degree in the gauge vector and its covariant derivatives.

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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex