大黄蜂引力中的带电粒子与场：周期轨道与超辐射
Charged particles and fields in bumblebee gravity: Periodic orbits and superradiance
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中文总结 AI 辅助
本研究探讨大黄蜂引力中带电黑洞周围带电粒子与场的动力学，发现最内层稳定圆轨道随洛伦兹破缺参数增大，并揭示了超辐射放大随参数变化及吸收截面的三区域特征。
中文摘要 AI 辅助
我们研究了在大黄蜂引力中带电黑洞背景下带电粒子和场的动力学，旨在更好地理解洛伦兹破缺参数 $l$ 所扮演的角色。我们首先回顾了带电大黄蜂黑洞的推导过程，并研究了其主要物理和几何性质。随后，我们获得了带电粒子的圆形轨道和束缚轨道，并发现最内层稳定圆轨道随 $l$ 增大而增大。通过数值方法，我们计算了任意标量波频率 $\omega$ 下的总吸收截面。由于时空并非渐近平坦，我们通过考虑修正后的渐近动量和通量来构建总吸收截面。在低频和高频区域推导出了解析近似。低频表达式展示了一个分离两个不同渐近分支的过渡速度，并推广了相应的赖斯纳-诺德斯特伦结果。我们关于截面的数值结果在相应极限下与解析近似一致，且吸收参数空间可分为三个区域：无界吸收、有界吸收和有界超辐射。特别地，每当 $\omega<\omega_{c}$ 时会发生超辐射，其中 $\omega_{c}$ 是超辐射的阈值。此外，超辐射放大随 $l$ 增大而减小，且 $l < 0$ 的带电大黄蜂黑洞比赖斯纳-诺德斯特伦情形产生更大的超辐射散射。我们还注意到，尽管增大 $l$ 会降低势垒，但由于截面公式中存在几何因子 $1/(1+l)$，总吸收截面反而减小。
英文摘要
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.
发表机构
- Faculdade de Ciências Naturais, Universidade Federal do Pará（帕拉拉联邦大学自然科学学院）
- Departamento de Física, Universidade Federal da Paraíba（帕拉伊巴联邦大学物理系）
- Instituto de Física, Universidade Federal Fluminense（弗鲁米嫩塞联邦大学物理研究所）
- Departamento de Física, Universidade Federal de Campina Grande（坎皮纳格兰德联邦大学物理系）
- Center for Theoretical Physics, Khazar University（阿塞拜疆可汗大学理论物理中心）
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