A classical solution where the (scalar) field value moves by an ${\cal O}(1)$ range in Planck units is believed to signal the breakdown of Effective Field Theory (EFT). One heuristic argument for this is that such a field will have enough energy to be inside its own Schwarzschild radius, and will result in collapse. In this paper, we consider an inverse problem: what kind of field ranges arise during the gravitational collapse of a classical field? Despite the fact that collapse has been studied for almost a hundred years, most of the discussion is phrased in terms of fluid stress tensors, and not fields. An exception is the scalar collapse made famous by Choptuik. We re-consider Choptuik-like systems, but with the emphasis now on the evolution of the scalar. We give strong evidence that generic spherically symmetric collapse of a massless scalar field leads to super-Planckian field movement. But we also note that in every such supercritical collapse scenario, the large field range is hidden behind an apparent horizon. We also discuss how the familiar perfect fluid models for collapse like Oppenheimer-Snyder and Vaidya should be viewed in light of our results.

中文翻译：

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重力倒塌中跨普朗克场范围的宇宙审查

一种经典的解决方案，其中（标量）场值以Planck单位移动$ {\ cal O}（1）$范围被认为是有效场论（EFT）崩溃的信号。关于此的一种启发式论证是，这样的场将具有足够的能量以位于其自身的Schwarzschild半径内，并会导致崩溃。在本文中，我们考虑一个反问题：经典场的引力坍塌过程中会出现哪种场范围？尽管已经对坍塌进行了近一百年的研究，但大多数讨论都是根据流体应力张量而不是场进行的。例外是Choptuik著名的标量崩溃。我们重新考虑类似Choptuik的系统，但现在重点放在标量的演化上。我们提供有力的证据，证明无质量标量场的一般球形对称塌陷会导致超普朗克场运动。但是，我们也注意到，在每一个这样的超临界崩溃场景中，大的视场都隐藏在视线的后面。我们还讨论了应如何根据我们的结果来观察熟悉的崩塌的理想流体模型，如Oppenheimer-Snyder和Vaidya。