Charged particles and fields in bumblebee gravity: Periodic orbits and superradiance
Abstract
We investigate the dynamics of charged particles and fields in the background of a charged black hole in bumblebee gravity, aiming to better understand the role played by the Lorentz-violating parameter l. We first review the derivation of the charged bumblebee black hole and investigate its main physical and geometrical properties. We then obtain the circular and bound trajectories of charged particles and find that the innermost stable circular orbit increases with l. By using a numerical approach, we compute the total absorption cross section for arbitrary values of the scalar wave frequency ω. Since the spacetime is not asymptotically flat, we construct the total absorption cross section by taking into account the modified asymptotic momentum and flux. Analytical approximations are derived in the low- and high-frequency regimes. The low-frequency expression displays a transition velocity that separates two distinct asymptotic branches and generalizes the corresponding Reissner-Nordström result. Our numerical results for the cross section agree with the analytical approximations in their corresponding limits, and the absorption parameter space can be divided into three regions: Unbounded absorption, bounded absorption, and bounded superradiance. In particular, superradiance occurs whenever ω<ωc, where ωc is the threshold for superradiance. Moreover, the superradiance amplification decreases as we increase l, and charged bumblebee black holes with l < 0 lead to greater superradiant scattering than in the Reissner-Nordström case. We also note that although increasing l lowers the potential barrier, it reduces the total absorption cross section because of the geometrical factor 1/(1+l) present in the cross section formula.
Related
- Testing charged bumblebee black holes through high-frequency quasi-periodic oscillations in X-ray binaries
- Magnetic fields of current loops and charged particles around black holes in modified gravity
- Magnetically charged spinning particles around a regular black hole: constraints on the monopole charge from quasi-periodic oscillations
- Periodic orbits around a magnetically charged black hole in f(R,T) gravity coupled with Euler-Heisenberg electrodynamics
- Gravitational-Wave Signatures and Periodic Orbits of Charged Particles Around a Five-Dimensional Rotating Black Hole: Comparison with the Kerr Black Hole
BibTeX
@misc{paula2026charged,
title = {{Charged particles and fields in bumblebee gravity: Periodic orbits and superradiance}},
author = {Marco A. A. de Paula and Renan B. Magalhães and V. B. Bezerra and A. A. Araújo Filho},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22482},
eprint = {2609.22482},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22482},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Charged particles and fields in bumblebee gravity: Periodic orbits and superradiance
AU - Marco A. A. de Paula
AU - Renan B. Magalhães
AU - V. B. Bezerra
AU - A. A. Araújo Filho
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22482
UR - https://arxiv.org/abs/2609.22482
AB - We investigate the dynamics of charged particles and fields in the background of a charged black hole in bumblebee gravity, aiming to better understand the role played by the Lorentz-violating parameter l. We first review the derivation of the charged bumblebee black hole and investigate its main physical and geometrical properties. We then obtain the circular and bound trajectories of charged particles and find that the innermost stable circular orbit increases with l. By using a numerical approach, we compute the total absorption cross section for arbitrary values of the scalar wave frequency ω. Since the spacetime is not asymptotically flat, we construct the total absorption cross section by taking into account the modified asymptotic momentum and flux. Analytical approximations are derived in the low- and high-frequency regimes. The low-frequency expression displays a transition velocity that separates two distinct asymptotic branches and generalizes the corresponding Reissner-Nordström result. Our numerical results for the cross section agree with the analytical approximations in their corresponding limits, and the absorption parameter space can be divided into three regions: Unbounded absorption, bounded absorption, and bounded superradiance. In particular, superradiance occurs whenever ω<ω_c, where ω_c is the threshold for superradiance. Moreover, the superradiance amplification decreases as we increase l, and charged bumblebee black holes with l < 0 lead to greater superradiant scattering than in the Reissner-Nordström case. We also note that although increasing l lowers the potential barrier, it reduces the total absorption cross section because of the geometrical factor 1/(1+l) present in the cross section formula.
ER -