潘多拉的盒盖：视视界附近的几何学
Pandora's box lid: geometry near the apparent horizon
摘要：
被视界包围的被困区域是黑洞的定义性特征。然而，在有限时间内，一个远距离观测者的无奇性视视界的形成只与其附近的特殊几何和物质状态相一致。在球对称中，这样的视界只存在于爱因斯坦方程的两类解中。两者都违反了零能量条件（NEC），并允许扩大和收缩捕获区域。然而，一个不断扩大的被困区域会导致防火墙。穿过这道防火墙的观察者的能量密度的加权时间平均值是负的，并且超过了量子场可以产生的最大NEC破坏。结果，要么黑洞只能蒸发，要么半经典物理学已经在视界上崩溃了。一个收缩的俘获区的几何形状随着质量的减小而接近进入的Vaidya度规。只有一类解允许测试粒子穿过视视界，并允许薄壳坍缩成黑洞。这些结果明显地限制了规则黑洞模型。只有当在视界尺度上已经发生了与半经典物理学的显著偏离时，才能实现在视界上具有规则物质性质的模型。海沃德-弗罗洛夫模型可能只描述了蒸发，而不是规则黑洞的形成。
英文摘要：
Trapped regions bounded by horizons are the defining features of black holes. However, formation of a singularity-free apparent horizon in finite time of a distant observer is consistent only with special states of geometry and matter in its vicinity. In spherical symmetry such horizons exist only in two classes of solutions of the Einstein equations. Both violate the null energy condition (NEC) and allow for expanding and contracting trapped regions. However, an expanding trapped region leads to a firewall. The weighted time average of the energy density for an observer crossing this firewall is negative and exceeds the maximal NEC violation that quantum fields can produce. As a result, either black holes only can evaporate or the semiclassical physics breaks down already at the horizons. Geometry of a contracting trapped region approaches the ingoing Vaidya metric with decreasing mass. Only one class of solutions allows for a test particle to cross the apparent horizon, and for a thin shell to collapse into a black hole. These results significantly constrain the regular black hole models. Models with regular matter properties at the horizon can be realized only if significant departures from the semiclassical physics occur already at the horizon scale. The Hayward-Frolov model may describe only evaporation, but not formation of a regular black hole.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
