AI 中文总结
该研究构建了Kerr-Bertotti-Robinson时空跨越$r=\infty$面的自然延拓，形成类虫洞连接的无限区域链，挑战弱宇宙监督猜想，并通过解析与分析证明存在不稳定拟正模，还发现弱阻尼拟正模暗示类回声响应。
AI 中文摘要
Kerr–Bertotti–Robinson（KBR，克尔-贝尔托蒂-罗宾逊）时空的$r=\infty$面并非无限延伸光线的端点集合，且由$Ψ_2$表示的引力场强库仑型分量在该处保持非零，表明该面并非真实边界。我们构建了一个跨越该面的自然延拓，将一个KBR区域的外部与相邻区域的内部连接起来，经迭代后可生成由类虫洞桥连接的无限区域链。该延拓还暴露了无中间视界的相邻环奇点，对弱宇宙监督猜想构成挑战，并引发了延拓几何在微扰下是否稳定的问题。因此我们研究了双宇宙散射段上测试无质量标量场的拟正模（QNMs）。对于轴对称微扰，我们解析证明了对每个$\ell$都存在纯虚数的不稳定QNM，其起源与破坏时序的区域相关。在$(\ell,m)=(2,2)$扇区中，发现了由黑洞炸弹机制驱动的不稳定QNM分支。最后，虫洞几何产生了双势垒腔和一系列弱阻尼QNM，暗示了类回声响应。
英文摘要
The surface $r=\infty$ of the Kerr--Bertotti--Robinson (KBR) spacetime is not the collection of the endpoints of infinitely extended light rays, and the Coulomb type component of gravitational field strength represented by $Ψ_2$ remains nonvanishing there, indicating that this surface is not a real boundary. We construct a natural extension across this surface, which connects the exterior of one KBR region to the interior of a neighboring one and, upon iteration, produces an infinite chain of regions connected by wormhole-like bridges. The extension also exposes the neighboring ring singularity without an intervening horizon, challenging the weak cosmic censorship conjecture and raising the question of whether the extended geometry is stable under perturbations. We therefore study the quasinormal modes (QNMs) of a test massless scalar field on a two-universe scattering segment. For axisymmetric perturbations, the existence of purely imaginary unstable QNMs is analytically proved for every $\ell$, with their origin tied to the chronology-violating region. In the $(\ell,m)=(2,2)$ sector, unstable QNM branches driven by a black-hole-bomb mechanism are found. Finally, the wormhole geometry produces a double-barrier cavity and families of weakly damped QNMs, suggesting echo-like responses.
Commentsrevtex4, 7 pages, 4 figures
