Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ghost condensate model of flat rotation curves   An effective action of ghost condensate with higher derivatives creates a
source of gravity and mimics a dark matter in spiral galaxies. We present a
spherically symmetric static solution of Einstein--Hilbert equations with the
ghost condensate at large distances, where flat rotation curves are reproduced
in leading order over small ratio of two energy scales characterizing constant
temporal and spatial derivatives of ghost field: mu_*^2 and mu_\star^2,
respectively, with a hierarchy mu_\star\ll \mu_*. We assume that a mechanism of
hierarchy is provided by a global monopole in the center of galaxy. An estimate
based on the solution and observed velocities of rotations in the asymptotic
region of flatness, gives mu_* ~ 10^{19} GeV and the monopole scale in a GUT
range mu_\star ~ 10^{16} GeV, while a velocity of rotation v_0 is determined by
the ratio: sqrt{2} v_0^2= mu_\star^2/mu_*^2. A critical acceleration is
introduced and naturally evaluated of the order of Hubble rate, that represents
the Milgrom's acceleration.

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The categories of this paper are: cond-mat
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The categories of this paper are: q-bio
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The categories of this paper are: physics
29
The categories of this paper are: funct-an
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The categories of this paper are: nlin
30
The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph