发表机构
Dalhousie University（达尔豪斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过微扰方法构造嵌入演化宇宙背景的中心不均匀性标量张量解，研究黑洞在非奇异反弹中的持续性，发现一个小演化视界支持黑洞存活。
AI 中文摘要
我们构建了一个微扰标量张量解，描述嵌入演化宇宙背景中的中心不均匀性，旨在研究黑洞通过非奇异反弹的持续性。标量张量引力为实现反弹宇宙学提供了自然框架，而包含局部不均匀性使场方程求解变得困难得多。因此，我们采用微扰方案，微扰参数为$\epsilon$，其中领头阶方程由辐射完美流体驱动的空间平坦反弹FLRW时空求解。在下一阶，通过广义McVittie几何引入中心不均匀性，扰动编码在相应的一阶度量和标量场函数中。我们首先允许具有径向和切向压力的各向异性流体，其对角分量求解对角场方程。场方程在反弹点$\eta=0$附近展开至$\mathcal{O}(\eta^4)$求解。得到的完美流体解包含三个任意函数，通过要求时空在$r\to\infty$时渐近为FLRW来约束这些函数。在保持反弹抛物线结构的适当初始条件下，积分常数$d_0$作为真正的微扰参数出现：当$d_0\to0$时所有扰动消失。最后，我们发现一个小演化视界$r_h\sim d_0$，我们将其解释为中心不均匀性的视界。它通过反弹的持续性支持了黑洞存活于宇宙转变的解释，并且其演化关于$\eta=0$不对称。
英文摘要
We construct a perturbative scalar-tensor solution describing a central inhomogeneity embedded in an evolving cosmological background, with the aim of studying black hole persistence through a nonsingular bounce. Scalar-tensor gravity provides a natural framework for realizing bouncing cosmologies, while the inclusion of a localized inhomogeneity makes the field equations substantially more difficult to solve. We therefore adopt a perturbative scheme, with perturbative parameter $ε$, in which the leading-order equations are solved by a spatially flat bouncing FLRW spacetime sourced by a radiation perfect fluid. At next order, a central inhomogeneity is introduced through a generalized McVittie geometry, with the perturbations encoded in the corresponding first-order metric and scalar-field functions. We first allow an anisotropic fluid with radial and tangential pressures, whose diagonal components solve the diagonal field equations. The field equations are solved as a series expansion up to $\mathcal{O}(η^4)$ near the bounce at $η=0$. The resulting perfect fluid solution contains three arbitrary functions which are constrained by requiring the spacetime to asymptote to FLRW as $r\to\infty$. With suitable initial conditions preserving the parabolic structure of the bounce, the integration constant $d_0$ emerges as the true perturbative parameter: all perturbations vanish as $d_0\to0$. Finally, we find a small evolving horizon, $r_h\sim d_0$, which we interpret as the horizon of the central inhomogeneity. Its persistence through the bounce supports the interpretation of a black hole surviving the cosmological transition, and its evolution is not symmetric about $η=0$.
Journal refGen. Relativ. Gravit. 58, 111 (2026)
DOI：10.1007/s10714-026-03610-6
