Quantum entanglement and wormholes

Quantum entanglement is a “weird” conduit between events in spacetime, not limited by the speed of light. Wormholes are also a “weird” conduit between events in spacetime, not limited by the speed of light. New research seems to imply that perhaps these two weird things are really one and the same.

Quantum entanglement is the “spooky action at a distance” that so puzzled Einstein (see the recent review of Rudy Rucker’s science fiction novel The Big Aha and the excellent Quantum Reality by Nick Herbert). But Bell and other physicists have shown that entanglement is real: there are faster than light correlations between entangled particles, and these faster than light correlations can be confirmed in the lab. But Einstein’s special relativity and many parts of modern physics would collapse if the instantaneous correlations between entangled particles could be used to send signals, actionable information. A no-communication theorem states that using spooky entangled correlations to send signals is impossible. Not everyone agrees though (see review of Einstein’s Bridge, by John G. Cramer)

Quantum objects exist in an indeterminate states, for example a particle can be spin-up AND spin-down (don’t try to visualize that, it is impossible). More correctly, the state of a quantum object cannot be described by intuitive macroscopic concepts like spin, position, velocity etc. Observation “collapses” a quantum state to a macroscopically defined state. For example, after observation the particle is spin-up OR spin-down. Please don’t ask what is an observation, or what/who can be an observer.

Particles that have interacted in the past can be “entangled.” For example the spin state of a system composed by particles 1 and 2 can be such that both spins are undetermined, but correlated: particle 2’s spin is down when particle 1’s spin is up, and vice versa. After observation, each particle has a determined spin, but the spins are always correlated, if the first is spin up the second is spin down and vice versa. The correlations between 1 and 2 seem instantaneous, not limited by the speed of light. This is confirmed by both theoretical analysis and experiments in the lab.

APS Synopsis: Entangled through a Wormhole“Quantum entanglement is weird enough, but it might get weirder still through a possible association with hypothetical wormholes. Over the past year, theorists have been hard at work exploring the entanglement of two black holes. A pair of papers in Physical Review Letters advances the story by showing that a string-based representation of two entangled quarks is equivalent to the spacetime contortions of a wormhole.”

“A common feature of entanglement and wormholes is that they both seemingly imply faster-than-light travel. If one imagines two entangled particles separated by a large distance — a so-called Einstein-Podolsky-Rosen (EPR) pair — then a measurement of one has an immediate effect on the measurement probabilities of the other, as if information travels instantaneously between them. Similarly, a wormhole — or Einstein-Rosen (ER) bridge — is a “shortcut” connecting separate points in space, but no information can actually pass through. Recent work has shown that the spacetime geometry of a wormhole is equivalent to what you’d get if you entangled two black holes and pulled them apart — an equivalence that can be summarized by “ER = EPR.””

An MIT press release says: “But what enables particles to communicate instantaneously — and seemingly faster than the speed of light — over such vast distances? Earlier this year, physicists proposed an answer in the form of “wormholes,” or gravitational tunnels. The group showed that by creating two entangled black holes, then pulling them apart, they formed a wormhole — essentially a “shortcut” through the universe — connecting the distant black holes.

“Now an MIT physicist has found that, looked at through the lens of string theory, the creation of two entangled quarks — the building blocks of matter — simultaneously gives rise to a wormhole connecting the pair.

“The theoretical results bolster the relatively new and exciting idea that the laws of gravity holding together the universe may not be fundamental, but arise from something else: quantum entanglement.”

An interesting connection between the mathematics of entanglement and the mathematics of quantum wormholes is all we have at this moment. But research will go on, and it may show that the connection is deeper.

Many 19th century physicists were puzzled by the similarity between gravity and inertia. Why should inertial mass and gravitational mass have the same value? These were two totally unrelated concepts in 10th century physics. But Einstein showed that these two previously unrelated concepts were really different aspects of one and the same thing.

General relativity was an elegant way to unify previously separated concepts. In physics, elegant explanation often work. Of course this result is no guarantee that future physicists will find that entangled quantum objects and wormholes are really aspects of the same thing, but it is an “interesting truth” (Ref. Greg Egan’s Incandescence) which shows that this may be a promising line of research.

In related news, Louisiana State University’s Mark Wilde has shown that it would theoretically be possible for time travelers to copy quantum data from the past (see Physical Review Letters and arXiv papers). The new approach allows for a particle, or a time traveler, to make multiple loops back in time. “That is, at certain locations in spacetime, there are wormholes such that, if you jump in, you’ll emerge at some point in the past,” Wilde said. “To the best of our knowledge, these time loops are not ruled out by the laws of physics.”

In The Light of Other Days, Sir Arthur C. Clarke and Stephen Baxter imagine a near future world profoundly transformed by the invention of a Wormcam: a remote viewing device that permits scanning any location at any time, including in the past, by using micro wormholes naturally embedded with high density in the fabric of space-time (every space-time pixel is connected with every other space-time pixel).

These results don’t tell us how to build a Wormcam, not yet, and they don’t provide proof that such a device is physically possible. A lot of theoretical and experimental work will be needed for that. But these results do show that quantum reality is weird enough to give plausibility to the intuition that every space-time pixel is connected to every other space-time pixels by information conduits that, perhaps, future engineers will be able to exploit with awesome results.