It has been said that Newton gave us answers; Stephen Hawking gave us questions. A trio of physicists seems one step closer to solving the black hole’s information paradox, one of the most intriguing physics mysteries of our time.

## Things can come out of a black hole both on the outside and possibly to another universe.”

“Space-time appears to be breaking up at a black hole, implying that space-time is not the root level of reality, as suggested by the famous paradox Stephen Hawking first described five decades ago, but arises from something deeper.” notices. George Musserauthor of Spooky Action at a Distance, for Quanta on Hawking’s groundbreaking theory that in a fiery marriage of relativity and quantum physics says that when a black hole is formed and then completely vaporized by emitting radiation, the information that has gone into the black hole can no longer come out and inevitably is lost, contrary to the laws of nature which state unequivocally that information can never be completely lost.

**Enter Einstein – The Dissolution of Spacetime**

In 2003, Hawking found a way for information to escape during the evaporation of the hole, but he didn’t prove that the information escapes, so the paradox has remained until now. “It’s not the eternal prisons they once thought of,” Hawking said. “Things can come out of a black hole, both to the outside and possibly to another universe.”

“While Einstein conceived of gravity as the curved geometry of space-time, his theory also entails the dissolution of space-time, which is ultimately why information can escape its gravitational prison,” Musser added, summarizing a historical series of calculations by three physicists together. showing that information escapes a black hole through the action of ordinary gravity with a single layer of quantum effects, which by definition seems impossible based on new gravity calculations that Einstein’s theory allows, but which Hawking did not include.

**“The most exciting thing since Hawking”**

“That’s the most exciting thing that’s happened in this topic, I think, since Hawking,” said one of the co-authors, Donald Marolfu from the University of California, Santa Barbara.

“From that mysterious area – where relativity and quantum mechanics don’t quite fit together, the question arises what happens to information inside a black hole,” says researcher Henry Maxfield at the University of California, Santa Barbara in calculating the quantum information content of a black hole and its radiation.

**The big question**

Maxfield co-authored a paper co-authored with physicists Ahmed Almheiri of the Institute for Advanced Study and MIT’s Netta Engelhardt and Marolf UC Santa Barbara in 2019 that brings us one step closer, says Maxfield, “to solving the black problem.” “The hope was that if we could answer this question — if we could see the information come out — we would have had to learn microscopic theory to do that,” said Geoff Penington of the University of California, Berkeley, hinting to a complete quantum theory of gravity.

**“Black holes glow and radiate softly”**

“It goes back to this problem in the 1970s that Stephen Hawking discovered,” explains Maxfield. Black holes – those extremely dense, high-gravity cavities in space-time – aren’t quite ‘black’. “They glow softly and shine,” he said. And as they do, the black holes evaporate. But one element of Hawking’s calculations, Maxfield continued, is that this state of “Hawking radiation” destroys information about the original quantum state of the material being drawn into the hole.

“This is very different from what quantum mechanics does,” Maxfield said. “In principle, the laws of physics are completely reversible.” In other words, information about the material’s original quantum state should exist in some form. “So there was a conflict that quantum mechanics behaves one way and gravity seems to behave another way.”

**Tip of the iceberg**

“We were interested in something that was closely related, trying to identify where the information is,” Maxfield said of the nonlinear path to their computation as “a modification of Hawking’s computation” — broadening it with a method for quantifying the information.

## Once the black hole has shrunk to half its size — it takes a very long time — the quantum information begins to come out. This is what you would expect from quantum mechanics.”

“So there’s that early radiation when the black hole is still young and it doesn’t actually contain any information,” Maxfield said of their calculation of how much information is stored in a black hole as it evaporates, and the finding that the amount of information does indeed decrease. over time… “But once the black hole has shrunk to half its size – it takes a very long time – the quantum information starts to come out. This is what you would expect from quantum mechanics.”

The calculation made by Maxfield, Englehardt, Almheiri and Geoff Penington (who was doing very similar work at Stanford at the same time), UC Santa Barbara reports, is just the tip of the iceberg.

**The biggest clue we’ve had**

“It doesn’t mean we’ve fully understood everything,” Maxfield said. “But it’s the biggest clue we’ve had for a long time about how this tension is resolved.”

“They found that the information is coming out even though they didn’t have all the reasons why it came out,” Marolf noted. “But the idea is that this is a first step. If you have a way to do that calculation, you should be able to open that calculation and find out what the physical mechanism is. This calculation is something that we expect will give us insight into quantum processes in black holes and how information comes out.”

“I’m very resistant to people coming in and saying, ‘I have a solution in just quantum mechanics and gravity,'” said a skeptic Nick Warner from the University of Southern California. “Because it’s taken us around in circles before.”

Max Goldberg via UC Santa Barbara and Quanta