Gravitational analog of Faraday rotation in the magnetized Kerr and Reissner-Nordstr”om spacetimes. (arXiv:2106.03520v4 [gr-qc] UPDATED)
<a href="http://arxiv.org/find/gr-qc/1/au:+Chakraborty_C/0/1/0/all/0/1">Chandrachur Chakraborty</a>
It is known that the gravitational analog of the Faraday rotation arises in
the rotating spacetime due to the nonzero gravitomagnetic field. In this paper,
we show that it also arises in the “nonrotating” Reissner-Nordstr”om
spacetime, if it is immersed in a uniform magnetic field. The non-zero angular
momentum (due to the presence of electric charge and magnetic field) of the
electromagnetic field acts as the twist potential to raise the gravitational
Faraday rotation as well as the gravitational Stern-Gerlach effect in the said
spacetimes. The twisting can still exist even if the mass of the spacetime
vanishes. In other words, the massless charged particle(s) immersed in a
uniform magnetic field are able to twist the spacetime in principle, and
responsible for the rotation of the plane of polarization of light. This, in
fact, could have applications in the basic physics and the analog models of
gravity. Here, we also study the effect of magnetic fields in the Kerr and
Reissner-Nordstr”om spacetimes, and we derive the exact expressions for the
gravitational Faraday rotation and the gravitational Stern-Gerlach effect in
the magnetized Kerr and Reissner-Nordstr”om spacetimes. Calculating the lowest
order of the gravitational Faraday effect arisen due to the presence of a
magnetic field, we show that the logarithm correction of the distance of the
source and observer in the gravitational Faraday rotation and gravitational
Stern-Gerlach effect for the said spacetimes is an important consequence of the
presence of the magnetic field. From the astrophysical point of view, our
result could be helpful to study the effects of (gravito)magnetic fields on the
propagation of polarized photons in the strong gravity regime of the collapsed
object.
It is known that the gravitational analog of the Faraday rotation arises in
the rotating spacetime due to the nonzero gravitomagnetic field. In this paper,
we show that it also arises in the “nonrotating” Reissner-Nordstr”om
spacetime, if it is immersed in a uniform magnetic field. The non-zero angular
momentum (due to the presence of electric charge and magnetic field) of the
electromagnetic field acts as the twist potential to raise the gravitational
Faraday rotation as well as the gravitational Stern-Gerlach effect in the said
spacetimes. The twisting can still exist even if the mass of the spacetime
vanishes. In other words, the massless charged particle(s) immersed in a
uniform magnetic field are able to twist the spacetime in principle, and
responsible for the rotation of the plane of polarization of light. This, in
fact, could have applications in the basic physics and the analog models of
gravity. Here, we also study the effect of magnetic fields in the Kerr and
Reissner-Nordstr”om spacetimes, and we derive the exact expressions for the
gravitational Faraday rotation and the gravitational Stern-Gerlach effect in
the magnetized Kerr and Reissner-Nordstr”om spacetimes. Calculating the lowest
order of the gravitational Faraday effect arisen due to the presence of a
magnetic field, we show that the logarithm correction of the distance of the
source and observer in the gravitational Faraday rotation and gravitational
Stern-Gerlach effect for the said spacetimes is an important consequence of the
presence of the magnetic field. From the astrophysical point of view, our
result could be helpful to study the effects of (gravito)magnetic fields on the
propagation of polarized photons in the strong gravity regime of the collapsed
object.
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