Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron stars as photon double-lenses: constraining resonant conversion
  into ALPs   Axion-photon conversion is a prime mechanism to detect axion-like particles
that share a coupling to the photon. We point out that in the vicinity of
neutron stars with strong magnetic fields, magnetars, the effective photon mass
receives comparable but opposite contributions from free electrons and the
radiation field. This leads to an energy-dependent resonance condition for
conversion that can be met for arbitrary light axions and leveraged when using
systems with detected radio component. Using the magnetar SGR J1745-2900 as an
exemplary source, we demonstrate that sensitivity to $|g_{a\gamma}| \sim
10^{-12}\,\rm{GeV^{-1}}$ or better can be gained for $m_a \lesssim 10^{-6}\,\rm
eV$, with the potential to improve current constraints on the axion-photon
coupling by more than one order of magnitude over a broad mass range. With
growing insights into the physical conditions of magnetospheres of magnetars,
the method hosts the potential to become a serious competitor to future
experiments such as ALPS-II and IAXO in the search for axion-like particles.

24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs