engleski

Influence of the vacuum polarization effect on the motion of charged particles in the magnetic field around a Schwarzschild black hole

The consequences of the vacuum polarization effect in magnetic fields around a Schwarzschild black hole on the motion of charged particles are investigated in this work. Using the weak electromagnetic field approximation, we discuss the nonminimal coupling between magnetic fields and gravity caused by the vacuum polarization and study the equations of motion for the case of a magnetic field configuration which asymptotically approaches a dipole magnetic field. It is shown that the presence of nonminimal coupling can significantly influence the motion of charged particles around black holes. In particular, the vacuum polarization effect, leading to strong amplification or suppression of the magnetic field strength around the event horizon (depending on the sign of the coupling parameter), can affect the scattering angle and minimal distance for the electrons moving in the gravitational field of the black hole as well as the dependence of these parameters on the asymptotic magnetic field strength, initial distance, and the black hole mass. It is further demonstrated that the nonminimal coupling between gravity and astrophysical magnetic fields, caused by the vacuum polarization, can cause significant changes of the parameter space corresponding to bound trajectories around the black hole. In certain cases, the bounded or unbounded character of a trajectory is determined solely by the presence of nonminimal coupling and its strength. These effects could in principle be used as observational signatures of the vacuum polarization effect and also to constrain the value of the coupling parameter.

Alternative gravity theories ; Fluids & classical fields in curved spacetime

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