Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-induced scalarization and magnetic fields   In the presence of certain non-minimal couplings between a scalar field and
the Gauss-Bonnet curvature invariant, Kerr black holes can scalarize, as long
as they are spinning fast enough. This provides a distinctive violation of the
Kerr hypothesis, occurring only for some high spin range. In this paper we
assess if strong magnetic fields, that may exist in the vicinity of
astrophysical black holes, could facilitate this distinctive effect, by
bringing down the spin threshold for scalarization. This inquiry is motivated
by the fact that self-gravitating magnetic fields, by themselves, can also
promote "spin-induced" scalarization. Nonetheless, we show that in the
\textit{vicinity of the horizon} the effect of the magnetic field $B$ on a
black hole of mass $M$, up to $BM\lesssim 1$, works \textit{against}
spin-induced scalarization, requiring a larger dimensionless spin $j$ from the
black hole. A geometric interpretation for this result is suggested, in terms
of the effects of rotation $vs.$ magnetic fields on the horizon geometry.

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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: stat