Testing "Spooky Action At A Distance"

The goofy world of quantum physics.

Background:

Imagine that a pair of electrons are shot out from the disintegration of some other particle, like fragments from an explosion. By law certain properties of these two fragments should be correlated. If one goes left, the other goes right; if one spins clockwise, the other spins counterclockwise.

That means, Einstein said, that by measuring the velocity of, say, the left hand electron, we would know the velocity of the right hand electron without ever touching it.

Conversely, by measuring the position of the left electron, we would know the position of the right hand one.

Since neither of these operations would have involved touching or disturbing the right hand electron in any way, Einstein, Podolsky and Rosen argued that the right hand electron must have had those properties of both velocity and position all along. That left only two possibilities, they concluded. Either quantum mechanics was "incomplete," or measuring the left hand particle somehow disturbed the right hand one.

But the latter alternative violated common sense. Such an influence, or disturbance, would have to travel faster than the speed of light. "My physical instincts bristle at that suggestion," Einstein later wrote.

Bohr responded with a six-page essay in Physical Review that contained but one simple equation, Heisenberg's uncertainty relation. In essence, he said, it all depends on what you mean by "reality."

Does this mean that one can have two entangled particles, separated by light years of space (one on earth, one on, say, Andromeda-5) and change the spin of one (therefore instanteously changing the spin of its partner) and therefore have the makings of an instanteous communications system?

Do sci-fi fans know if "quantum radio" is usually the explanation for FTL communications?

posted by Ace at 06:20 PM

| Access Comments