Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kerr black holes with synchronised axionic hair   We construct and analyse Kerr black holes (BHs) with synchronised axionic
hair. These are the BH generalisations of the recently constructed rotating
axion boson stars arXiv:2005.05982. Such BHs are stationary, axially symmetric,
asymptotically flat solutions of the complex Einstein-Klein-Gordon theory with
a QCD axion-like potential. They are regular everywhere on and outside the
event horizon. The potential is characterised by two parameters: the mass of
the axion-like particle, $m_a$ and the decay constant $f_a$. The limit $f_a
\rightarrow \infty$ recovers the original example of Kerr BHs with synchronised
scalar hair arXiv:1403.2757. The effects of the non-linearities in the
potential become important for $f_a \lesssim 1$. We present an overview of the
parameter space of the solutions together with a study of their basic geometric
and phenomenological properties, for an illustrative value of the coupling that
yields a non-negligible impact of the self-interactions.

34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph