Mass inflation is a well established instability, conventionally associated to Cauchy horizons (which are also inner trapping horizons) of stationary geometries, leading to a divergent exponential buildup of energy. We show here that finite (but often large) exponential buildups of energy are present for dynamical geometries describing accreting black holes with slowly evolving inner trapping horizons, even in the absence of Cauchy horizons. The explicit evaluation of the adiabatic conditions behind these exponential buildups shows that this phenomenon is universally present for physically reasonable accreting conditions. This noneternal mass inflation does not require the introduction of global spacetime concepts. We also show that various known results in the literature are recovered in the limit in which the inner trapping horizon asymptotically approaches a Cauchy horizon. Our results imply that black hole geometries with nonextremal inner horizons, including the Kerr geometry in general relativity, and nonextremal regular black holes in theories beyond general relativity, can describe dynamical transients but not the long-lived end point of gravitational collapse.

中文翻译：

---

没有柯西视野的大规模膨胀


质量膨胀是一种公认的不稳定性，通常与静止几何的柯西视界（也是内部诱捕视界）有关，导致能量的发散指数积累。我们在这里表明，即使在没有柯西视界的情况下，描述具有缓慢演变的内部捕获视界的吸积黑洞的动力学几何也存在有限（但通常是大的）指数能量积累。对这些指数累积背后的绝热条件的明确评估表明，这种现象在物理上合理的吸积条件下普遍存在。这种非永恒的质量膨胀不需要引入全球时空概念。我们还表明，文献中的各种已知结果都在内部诱捕视界渐近接近柯西视界的极限中恢复。我们的结果表明，具有非极值内视界的黑洞几何，包括广义相对论中的克尔几何，以及广义相对论之外理论中的非极值规则黑洞，可以描述动力学瞬态，但不能描述引力坍缩的长期终点。