DENVER: Researchers have developed a new, incredibly dangerous and incredibly slow method of crossing the universe. These are wormholes that link special black holes that probably do not exist. And it could explain what is really happening when physicists teleport information from one point to another, from the perspective of the teleported information bit.
Daniel Jafferis, a physicist at Harvard University, described the method proposed in a talk on April 13 here at a meeting of the American Physical Society. This method, he told his badembled colleagues, involves two black holes that get entangled so they are connected through space and time.
What is a wormhole?
His idea solves a long-standing problem: when something enters a wormhole, it takes negative energy to get out the other side. (Under normal circumstances, the shape of spacetime at the exit of a wormhole makes it impossible to pbad, but a substance with negative energy could, in theory, overcome that obstacle). But nothing in the physics of gravity and spacetime. The physics that describes wormholes allows that kind of pulses of negative energy. So wormholes are impossible to go through.
"It's just a connection in space, but if you try to get through it, it collapses too fast so you can not get through it," Jafferis told Live Science after his talk. [9 Ideas About Black Holes That Will Blow Your Mind]
This older wormhole model can be traced back to an article by Albert Einstein and Nathan Rosen, published in Physical Review in 1935. The two physicists realized that, under certain circumstances, relativity would dictate that space-time would be curved so extremely that a kind of tunnel (or "bridge") would join two separate points.
Physicists wrote the article partly to exclude the possibility of black holes in the universe. But in later decades, when physicists realized that black holes exist, the standard image of a wormhole became a tunnel where the two openings appear as black holes. However, according to this idea, just as a tunnel would probably never exist naturally in the universe, and if it existed, it would disappear before anything happened through it. In the 1980s, physicist Kip Thorne wrote that something could happen through this wormhole if some kind of negative energy were applied to keep the wormhole open.
Jafferis, along with Harvard physicist Ping Gao and Stanford physicist Aron Wall, have developed a way to apply a negative energy version that is based on an idea from a very different area of physics, called entanglement.
The entanglement comes from quantum mechanics, not from relativity. In 1935, Albert Einstein, Boris Podolsky and Nathan Rosen published another article in Physical Review that shows that under the rules of quantum mechanics the particles can be "correlated" with each other, so that the behavior of a particle directly impacts the behavior of other. [The 18 Biggest Unsolved Mysteries in Physics]
Einstein, Podolsky and Rosen thought that this proved that something was wrong with their ideas of quantum mechanics, because it would allow information to move faster than the speed of light between the two particles. Now, physicists know that entanglement is real, and quantum teleportation is an almost routine part of physics research.
This is how quantum teleportation works: Engage two light particles, A and B. Then, give B to your friend to take him to another room. Next, hit a third photon, C, against photon A. That entangles A and C, and breaks the tangle between A and B. Then you can measure the combined state of A and C, which is different from the original states of A , B or C: communicate the results of the combined particles to your friend in the next room.
Without knowing the state of B, your friend can use that limited information to manipulate B to produce the state that particle C had at the beginning of the process. If you measure B, you will learn the original state of C, without anyone telling you. Information about the particle C functionally teleported from one room to another.
This is useful, since it can act as a type of code that can not be deciphered to send messages from one point to another.
And entanglement is not just a property of individual particles. Larger objects can also be entangled, although the perfect entanglement between them is much more difficult.
Tangled black holes can transport you
In 1935, the physicists who wrote these documents had no idea that wormholes and entanglements were connected, said Jafferis. But in 2013, physicists Juan Maldacena and Leonard Susskind published an article in the journal Progress in Physics that links the two ideas. They argued that two perfectly tangled black holes would act like a wormhole between their two points in space. They called the idea "ER = EPR" because it linked the role of Einstein-Rosen with that of Einstein-Podolsky-Rosen.
When asked if there really could be two completely tangled black holes in the universe, Jafferis said: "No, no, certainly not."
It is not that the situation is physically impossible. It is too precise and huge for our messy universe to produce. Producing two perfectly entwined black holes would be like winning the lottery, only a million million times less likely.
And if they did exist, he said, they would lose their perfect correlation at the moment when a third object interacted with one of them.
But if, somehow, such a pair existed, somehow, somewhere, then the method of Jafferis, Gao and Wall could work.
His approach, published for the first time in The Journal of High Energy Physics in December of 2017, is like this: throw your friend into one of the tangled black holes. Then, measure the so-called Hawking radiation that comes out of the black hole, which encodes some information about the state of that black hole. Then, take that information to the second black hole and use it to manipulate the second black hole. (This can be as simple as throwing a large amount of Hawking radiation from the first black hole to the second). In theory, your friend should leave the second black hole exactly as he entered the first.
From her perspective, said Jafferis, she would have dived into a wormhole. And as she approached the singularity in her neck, she would have experienced a "pulse" of negative energy that would have driven her to the other side. [What Would Happen If You Fell into a Black Hole?]
The method is not particularly useful, said Jafferis, because it would always be slower than physically moving the distance between the two black holes. But it does suggest something about the universe.
From the perspective of a little information that pbades between tangled particles, said Jafferis, something similar could be happening. On the scale of individual quantum objects, he said, it really does not make sense to talk about the space-time curve to produce a wormhole. But it involves a few more particles in the mix for a little more complex quantum teleportation, and suddenly the wormhole model makes a lot of sense. There is strong evidence here, he said, that the two phenomena are related.
He also strongly suggests, he said, that information lost in a black hole could go somewhere where it could one day be recovered.
If you fall into a black hole tomorrow, he said, all hope is not lost. A sufficiently advanced civilization could be able to zoom across the universe, collecting all the Hawking radiation emitted by the black hole as it slowly evaporated over eons, and compressing that radiation into a new black hole, entangled with the original through time. Once that new black hole emerged, it might be possible to recover it from him.
Theoretical research on this method of movement among black holes, said Jafferis, is ongoing. But the goal is more to understand fundamental physics than perform black hole rescues. Then, maybe it's better not to risk it.
Originally published in Living science.