Carrollian motion in magnetized black hole horizons
Finnian Gray, David Kubizňák, T. Rick Perche, Jaime Redondo–Yuste
Abstract
We revisit the motion of massless particles with anyonic spin in the horizon of Kerr-Newman geometry. As recently shown, such particles can move within the horizon of the black hole due to the coupling of charges associated with a two-parametric central extension of the two-dimensional Carroll group to the magnetic field generated by the black hole---the so-called ``anyonic spin-Hall effect.'' We show that the previously computed magnetic field is not invariant under Carroll diffeomorphisms and find another result which respects these symmetries of the horizon. We also consider a more astrophysically relevant case of a (weakly charged) rotating back hole placed in a uniform magnetic field, which could, for instance, be induced by the surrounding plasma. We show that a qualitatively similar magnetic field assisted anyonic spin-Hall effect takes place, even in the absence of black hole rotation. The theoretical possibility of a motion induced by a magnetic monopole is also studied.