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arXiv · 2211.14760

Gravitational collapse and formation of a black hole in a type II minimally modified gravity theory

Antonio De Felice·Kei-ichi Maeda·Shinji Mukohyama·Masroor C. Pookkillath
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Abstract

We study the spherically symmetric collapse of a cloud of dust in VCDM, a class of gravitational theories with two local physical degrees of freedom. We find that the collapse corresponds to a particular foliation of the Oppenheimer-Snyder solution in general relativity (GR) which is endowed with a constant trace for the extrinsic curvature relative to the time $t$ constant foliation. For this solution, we find that the final state of the collapse leads to a static configuration with the lapse function vanishing at a radius inside the apparent horizon. Such a point is reached in an infinite time-$t$ interval, $t$ being the cosmological time, i.e. the time of an observer located far away from the collapsing cloud. The presence of this vanishing lapse endpoint implies the necessity of a UV completion to describe the physics inside the resulting black hole. On the other hand, since the corresponding cosmic time $t$ is infinite, VCDM can safely describe the whole history of the universe at large scales without knowledge of the unknown UV completion, despite the presence of the so-called shadowy mode.

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Antonio De Felice, Kei-ichi Maeda, Shinji Mukohyama, Masroor C. Pookkillath. 2022-11-27. Gravitational collapse and formation of a black hole in a type II minimally modified gravity theory. https://doi.org/10.1088/1475-7516%2F2023%2F03%2F030

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