Remarkably, this kind of efficiency occurs wherever there is a horizon that allows information to travel in only one direction, creating the possibility of a causal paradox. Another example is the edge of the known universe, called the cosmological horizon. Or think of the “Rindler horizon” behind an observer that constantly accelerates and approaches the speed of light so that light rays cannot reach them. All of these “killing horizons” (named after the late 19th and 20th century German mathematician Wilhelm Kieling) make quantum superposition possible. “These horizons are actually looking at you the same way,” says Satishchandran.
It is not entirely clear what exactly the known edge of the universe means to look at everything in the universe. “We don’t understand the cosmological horizon,” Lupsaska said. “It’s very attractive, but it’s harder than black holes.”
In any case, by conducting such thought experiments when gravity and quantum theory collide, physicists hope to discover the nature of a unified theory. “This is giving us some more clues about quantum gravity,” Wald said. For example, the new effect may help theorists understand how entanglement relates to space-time.
“These effects should be part of the ultimate story of quantum gravity,” Lupskaska said. “Now, would they be a crucial clue on the way to understanding that concept? It’s worth checking out.”
The participating universe
As scientists continue to learn about efficiency in all its forms, Wheeler’s concept of a participatory universe is becoming clearer, Danielson said. All the particles in the universe seem to exist in a subtle hyperspace until they are observed. Certainty comes through interaction. “I think that’s what Wheeler had in mind,” Danielson said.
And as black holes and other killer horizons observe everything all the time, “like it or not,” the participatory universe is “more evocative” than other forms of obscurity, the authors said.
Not everyone is ready to buy into Wheeler’s philosophy on a grand scale. “The idea that the universe is watching itself? That sounds a little Jedi to me,” Lupsaka says, though she agrees that “everything is always interacting and watching itself.”
“Poetically, you can think of it that way,” Carney said. “Personally, I’d say that the presence of the horizon means that the surrounding fields will stick out from the horizon in an amazing way.”
Wald When Wheeler first drew the “Big U” as a student in the 1970s, Wald didn’t think much of it. “I was struck by the fact that Wheeler’s idea was not so well founded.
Anna now? “A lot of what he did was curiosity and some vague ideas,” Wald said, noting that Wheeler was anticipating Hawking’s radiation long before the results counted.
“He saw himself as holding out a beacon of light to light the paths that others might follow.”
Original story Reprinted with permission Quanta Magazine, Editorially independent publication Simons Foundation Its mission is to advance public understanding of science by covering research developments and trends in the mathematical and physical and life sciences.