But wait, something even stranger is going on here. Given the geometry that we have assumed (which is perfectly acceptable by the laws of physics) the “influence” has to travel from A to B much faster than the speed of light. Since the theory of special relativity tells us that no matter or energy could possibly travel faster than the speed of light, we have a problem.
This crossed a line for Einstein and his pals. His theory of special relativity had established the speed of light as a universal speed limit. Einstein dismissed as “spooky action at a distance” the notion that a measurement on one particle could have an influence on another particle one light year away in less than a second. This must mean, he and his co-authors concluded, that something was amiss with quantum physics.
One possibility is that quantum physics is not a local theory. Locality implies that particles can only influence one another if they are close together. If they are far apart, one can influence the other only by sending something to bridge the intervening space, like some sort of “messenger” particle. The fastest particles out there are photons, so the speed of light limits how fast electron e1 can cause a change to electron e2 that is located some distance away. (These ideas are incorporated into quantum field theories, which we will discuss.)
DEFINITION
Locality in physics means that no influence from one particle to another can be transmitted faster than the speed of light.
You can imagine that the Copenhagen interpretation of the paradox did not sit well with Einstein, who was after all the architect of special relativity and the one who discovered that nothing could travel faster than the speed of light. He and his colleagues therefore settled on the only other possible conclusion.
Leave a Reply