Dynamics of magnetized particles around a charged rotating BH in gravity with a background KR field
Shokhzod Jumaniyozov
1
,
Akhror Ortikov
1,*
1 New Uzbekistan University , Movarounnahr Street 1, Tashkent 100000, Uzbekistan
Abstract
We investigate the dynamics of magnetized particles orbiting a charged, rotating black hole (BH) in the presence of a background Kalb-Ramond (KR) field, a string theory-inspired modification to general relativity. Using the Hamilton-Jacobi formalism, we derive the equations of motion for particles with magnetic dipole moments, accounting for their interaction with the electromagnetic field modified by the KR field. The effective potential, innermost stable circular orbits (ISCOs), and orbital stability are analyzed as functions of the BH's charge, spin, and the Lorentz-violating KR parameter. Our results demonstrate that the KR field significantly alters spacetime geometry and electromagnetic interactions, leading to observable shifts in ISCO radii and orbital energy compared to Kerr-Newman or Schwarzschild BHs. We apply our model to the magnetar PSR J1745-2900, which orbits Sgr A*, demonstrating how the KR field's influence can manifest in astrophysical observables such as synchrotron emission and pulsar timing. These findings provide a framework for testing string-theory-motivated gravity in extreme environments using current and future observations from the Event Horizon Telescope and other high-precision instruments.
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Cite this article
Jumaniyozov, Sh. and Ortikov, A., Dynamics of magnetized particles around a charged rotating BH in gravity with a background KR field, Turanian J. Vol. 1, No. 4 (010404), 2025