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How short can the hair of a black hole be?

Darío Núñez·Hernando Quevedo·Daniel Sudarsky
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Abstract

We show that in all theories in which black hole hair has been discovered, the region with non-trivial structure of the non-linear matter fields must extend beyond $3/ 2$ the horizon radius, independently of all other parameters present in the theory. We argue that this is a universal lower bound that applies in every theory where hair is present. This {\it no short hair conjecture} is then put forward as a more modest alternative to the now debunked {\it no hair conjecture}.

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Darío Núñez, Hernando Quevedo, Daniel Sudarsky. 1995-10-17. How short can the hair of a black hole be?. https://arxiv.org/abs/gr-qc/9510036

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