Scientists may have solved Stephen Hawking's black hole paradox

black hole
Credit: CC0 Public Domain

Researchers may have solved Professor Stephen Hawking's famous black hole paradox—a mystery that has puzzled scientists for almost half a century.

According to two new studies, something called "quantum hair" is the answer to the problem.

In the first paper, published in the journal Physical Review Letters, researchers demonstrated that are more complex than originally thought and have gravitational fields that hold information about how they were formed.

The researchers showed that matter collapsing into a black hole leaves a mark in its —an imprint referred to as a "quantum hair."

In a follow-up paper, published in a separate journal, Physics Letters B, Professor Xavier Calmet from the University of Sussex's School of Mathematical and Physical Sciences and Professor Stephen Hsu from Michigan State University said quantum hairs resolve Hawking's Black Hole Information Paradox.

In 1976, Hawking suggested that, as black holes evaporate, they destroy information about what had formed them.

That idea goes against a fundamental law of which states any process in physics can be mathematically reversed.

In the 1960s, physicist John Archibald Wheeler, discussing black holes' lack of observable features beyond their total mass, spin, and charge, coined the phrase "black holes have no hair"—known as the no-hair theorem.

However, the newly discovered "quantum hair" provides a way for information to be preserved as a black hole collapses and, as such, resolves one of 's most famous quandaries, experts say.

Prof Calmet said: "Black holes have long been considered the perfect laboratory to study how to merge Einstein's theory of general relativity with quantum mechanics.

"It was generally assumed within the that resolving this paradox would require a huge paradigm shift in physics, forcing the potential reformulation of either quantum mechanics or general relativity.

"What we found—and I think is particularly exciting—is that this isn't necessary."

Explaining the discovery of the "quantum hair," Roberto Casadio, professor of Theoretical Physics at the University of Bologna, said: "A crucial aspect is that black holes are formed by the collapse of compact objects and then, according to the , there is no absolute separation between the interior and the exterior of the black hole.

"In the , the horizon acts as a perfect one-way membrane which does not let anything out and the exterior is therefore the same for all black holes of a given mass. This is the classical no-hair theorem," Casadio added.

"However, in the quantum theory, the state of the matter that collapses and forms the black hole continues to affect the state of the exterior, albeit in a way that is compatible with present experimental bounds. This is what is known as 'quantum hair.'"

More information: Xavier Calmet et al, Quantum hair and black hole information, Physics Letters B (2022). DOI: 10.1016/j.physletb.2022.136995

Xavier Calmet et al, Quantum Hair from Gravity, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.128.111301

2022 dpa GmbH.
Distributed by Tribune Content Agency, LLC.

Citation: Scientists may have solved Stephen Hawking's black hole paradox (2022, March 18) retrieved 22 September 2023 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Wormholes help resolve black hole information paradox


Feedback to editors