I think I might have mentioned once or twice that the realm of quantum mechanics is a rather odd one.
It’s the place where Newton’s familiar laws of physics — like, you know, gravity — lose their sway to the forces that govern the behavior of atoms, oddly named things like the weak nuclear force. (As an aside, it is probably because nanotechnology has one foot in the realm of quantum mechanics, and one in Newtonian physics that its materials have such wondrous properties that scientists are now eagerly seeking to exploit.)
But I digress. Tom Paulson of the Seattle Post-Intelligencer has written a wonderful article on some esteemed scientists in the great Northwest who are prying away at one of the oddities in quantum mechanics. Their goal? Retrocausality. In other words, they’re dabbling in time travel.
The real trouble with quantum mechanics, to professors and poor physics students alike, is that its explanations of the natural world are quite often counterintuitive. Perhaps the most famous of these apparent contradictions is Schrodinger’s Cat.
In any case, the whole notion of quantum mechanics is so weird that Einstein had a distinct dislike for the science and its host of paradoxes. Let’s have Paulson take up the story from here:
One of the paradoxes of interest to Cramer is known as “entanglement.” It’s also known as the Einstein-Podolsky-Rosen paradox, named for the three scientists who described its apparent absurdity as an argument against quantum theory.
Basically, the idea is that interacting, or entangled, subatomic particles such as two photons — the fundamental units of light — can affect each other no matter how far apart in time or space.
“If you do a measurement on one, it has an immediate effect on the other even if they are separated by light years across the universe,” Cramer said. If one of the entangled photon’s trajectory tilts up, the other one, no matter how distant, will tilt down to compensate.
Einstein ridiculed the idea as “spooky action at a distance.” Quantum mechanics must be wrong, the father of relativity contended, because that behavior requires some kind of “signal” passing between the two particles at a speed faster than light.
This is where going backward in time comes in. If the entanglement happens (and the experimental evidence, at this point, says it does), Cramer contends it implies retrocausality. Instead of cause and effect, the effect comes before the cause. The simplest, least paradoxical explanation for that, he says, is that some kind of signal or communication occurs between the two photons in reverse time.
The article goes into much more detail, but the bottom line is that Cramer and some colleagues have developed an elegant experiment to test whether such “communication” or “signal” actually exists. Few scientists think it actually does, but they struggle to explain why the experiment shouldn’t work.
And if it works? I should think bookies might be a little nervous were I able to get a call about a football game’s result before it has begun.
(Found via Centauri Dreams.)