Dynamics of test particles around renormalization group improved Schwarzschild black holes

TL;DR

This paper studies the motion of neutral, charged, and magnetized particles around renormalization group improved Schwarzschild black holes, analyzing spacetime structure, particle orbits, and effects of external magnetic fields, revealing limitations in mimicking rotating black holes.

Contribution

It introduces the dynamics of particles around RGI Schwarzschild black holes, including effects of parameters on orbits and the influence of magnetic fields, highlighting differences from Kerr black holes.

Findings

Curvature becomes infinite only at the center when γ=0.

RGI black hole parameters can mimic Kerr black hole rotation up to a/M ≈ 0.31.

Parameters of RGI black holes cannot replicate the high spin of astrophysical black holes.

Abstract

In this paper we have investigated the dynamics of neutral, electrically charged and magnetized particles around renormalized group improved (RGI) Schwarzschild black hole in the presence of external asymptotically uniform magnetic field. We have analyzed the spacetime structure around RGI black hole by investigating Ricci, the square of Ricci tensor and Kretschmann curvature scalars and shown that only in the case when the parameter $\gamma=0$ the curvature becomes infinite at the center of the black hole, while for non-zero values of $\gamma$ parameter the black hole curvature reflects the properties of regular black hole. Analyzing the innermost stable circular orbits of test neutral particles around RGI black hole and comparing with the results for rotating Kerr black hole we have shown that RGI black hole parameters can mimic the rotation parameter of Kerr black hole upto $a/M \lesssim 0.31$ providing the same ISCO radius. Since according to the astronomical observations of the accretion disks confirm that the astrophysical black holes are rapidly rotating with the spin parameter upto $a/M \sim 0.99$ one may conclude that the effects of parameters of RGI Schwarzschild black hole on the circular orbits of the neutral particles can not mimic the Kerr black hole. Then the Hamilton-Jacobi equation has been used to analyze the charged and magnetized particles motion near the RGI black hole in the presence of the strong interaction between external asymptotically uniform magnetic (electromagnetic) field and magnetized (electrically charged) particle. We have shown that RGI black hole parameters quantitatively change the dynamics of the charged and magnetized particles, in particular ISCO radius of the particles decreases with increasing the parameter $\lambda$, while the increase of the parameter $\gamma$ causes to increase of it.