发表机构
National University of Singapore（新加坡国立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
构造了Bertotti--Robinson磁背景中膨胀Reissner--Nordström黑洞的精确静态解，揭示视界响应与磁反转尺度，并验证了场方程。
AI 中文摘要
我们构造了四维爱因斯坦-麦克斯韦-膨胀理论的一个精确静态、带磁荷的解，该解推广了Bertotti--Robinson磁背景中的中心Reissner--Nordström黑洞。其纯背景极限是Bertotti--Robinson时空的磁EMD变形。利用Emparan--Teo解生成技术，带电构造在正则Weyl坐标中简化为将Schwarzschild视界杆替换为半长σ=√(m²-e²)的Reissner--Nordström杆，并积分所得非线性背景-杆相互作用。这给出了任意膨胀耦合α下的完全显式解，具有预期的特殊极限和完整场方程的数值验证。视界对单极-背景相互作用表现出耦合的力学、电磁和内在响应。残余锥形应力与南北磁极化相关；增加背景场产生有序反转尺度B_pole<B_crit<B_eq，在固定种子参数(m,e)下与α无关，而Gauss--Bonnet将锥形应力与奇异极点处的积分分布高斯曲率贡献联系起来。沿此处考虑的固定-(m,B,α,C)近极端路径，每个α>0给出消失的视界面积和发散曲率，而相关的近极端强场极限产生普遍的磁反转定律。
英文摘要
We construct an exact static, magnetically charged solution of four-dimensional Einstein--Maxwell--dilaton theory that generalizes the centered Reissner--Nordström black hole in a Bertotti--Robinson magnetic background. Its pure-background limit is the magnetic EMD deformation of Bertotti--Robinson spacetime. Using the Emparan--Teo solution-generating technique, the charged construction reduces in canonical Weyl coordinates to replacing the Schwarzschild horizon rod by the Reissner--Nordström rod of half-length $σ=\sqrt{m^2-e^2}$ and integrating the resulting nonlinear background--rod interaction. This yields a completely explicit solution for arbitrary dilaton coupling $α$, with the expected special limits and numerical verification of the full field equations. The horizon exhibits a coupled mechanical, electromagnetic and intrinsic response to the monopole--background interaction. The residual conical stress is tied to north--south magnetic polarization; increasing the background field produces the ordered reversal scales $B_{\rm pole}<B_{\rm crit}<B_{\rm eq}$, independent of $α$ at fixed seed parameters $(m,e)$, while Gauss--Bonnet identifies the conical stress with the integrated distributional Gaussian-curvature contribution at the singular pole. Along the fixed-$(m,B,α,C)$ near-extremal path considered here, every $α>0$ gives vanishing horizon area and divergent curvature, whereas a correlated near-extremal strong-field limit yields a universal magnetic-reversal law.
