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arXiv · 2508.02100

Formation of Frozen Stars from collapsing matter by tunneling

Ram Brustein·A. J. M. Medved·Tamar Simhon
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Abstract

The frozen star is a type of black hole mimicker: An ultracompact object whose exterior geometry resembles that of a general-relativistic black hole but differs in its matter composition and in the regularity of its interior geometry. It is sourced by a spherically symmetric collection of open-string flux tubes, which posses an extremely anisotropic energy-momentum-stress tensor with maximally negative radial pressure. The frozen star represents an effective classical description of the highly quantum, closed-string polymer model. A key challenge for any model of a black hole mimicker is to explain how such objects can form from a collapsing body of matter. We started to address this important problem in a previous article by adapting the Euclidean-action method of Gibbons and Hawking to show that the transition into a frozen star is likely. Here, we improve on our previous results by showing that the transition probability for a collapsing shell of matter to tunnel quantum mechanically into a frozen star is unity, up to negligible corrections. Our conclusion is that such a transition is therefore inevitable.

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Ram Brustein, A. J. M. Medved, Tamar Simhon. 2025-08-04. Formation of Frozen Stars from collapsing matter by tunneling. https://arxiv.org/abs/2508.02100

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