One of the goals of modern physics is to unite all the various theories of how the universe works. The latest attempt seeks to tie together entanglement — Einstein’s “spooky particles at a distance” — and the wormholes that bridge two black holes separated by vast distances. Along the way, though, this unification of theories might also reveal how space-time itself depends upon the entanglement of quantum particles.
Both entanglement and wormholes were proposed by Einstein in 1935. But until this recent development, these ideas were thought to be entirely unrelated. According to the physicists who are developing this new connection, however, those ideas are not only related, but are manifestations of the same thing. If this connection holds, it would provide a foundation for space-time itself.
“In other words, the solid and reliable structure of space-time is due to the ghostly features of entanglement,” Juan Maldacena, a physicist at the Institute for Advanced Study in Princeton, N.J., told Quanta Magazine.
Their theory might also address how gravity and quantum mechanics fit together.
The new line of thought encompasses many standard concepts in modern physics, such as the hologram, and some entirely new ideas, like black hole firewalls.
The holographic principle is a fairly-seasoned idea which proposes that information describing the universe requires one less dimension than the actual universe — much like a two-dimensional hologram on a credit card gives the appearance of a three-dimensional object. But this theory also describes how information that falls down a black hole is not lost, but is trapped on the two-dimensional event horizon — the surface of a black hole that marks the point of no return.
If all this information remains on the event horizon, then that leaves the question of what is going on in the interior of a black hole. In 2012 a group of physicists at Santa Barbara proposed that black holes might not even have insides. Instead, a “firewall” located just inside the event horizon would destroy anything trying to pass through.
The firewall concept effectively makes the areas inside and outside the event horizon independent. But Maldacena and Leonard Susskind, who helped develop the new unifying idea, suggest that entangled particles on either side could be connected by a wormhole. In their paper (pdf) describing their idea, the physicists depict this as multiple wormholes leading out of black hole, in something that resembles an octopus.
These wormholes provide a path for entangled particles to leave the inside of the black hole — without having to pass through the event horizon. Right now, this new idea applies only to a special type of wormhole and a special kind of entanglement. But physicists are excited about the implications as they move forward to ever more unified theories.