[extropy-chat] HISTORY: Solved & Unsolved Riddles

[John K Clark]

P.A.M. Dirac Wrote in  Principles of Quantum Mechanics:

"Each photon then interferes only with itself. Interference
between two different photons can never occur."

scerir <scerir at libero.it> Wrote:

  >Unfortunately the last sentence is dead wrong,
  >and the first is imprudent

Well, if you fire a bunch of photons at 2 slits you get the same pattern if
you send them one at a time as you do if you send them all at once; the only
difference is the pattern takes longer to form. If they interfered with each
other you'd think there would be a difference.

  >the experimental *smooth* transition between the wave-like and the
  >particle-like behaviour forbids an interpretation which acknowledges
  >the status of only one of the two properties of the "entity".

But the transition is never smooth, in the 2 slit experiment the photons act
like waves until they hit the photographic plate, then they don't produce a
smudge at you'd expect a wave to do, they make a point as you'd expect a
particle to do.

  >In general the "entity" can be seen as a carrier of information

I don't see how it can carry information if you can never detect it. We can
never detect the "entity" directly because it isn't even a probability, it's
the square root of a probability and being a square root means it can and
does have negative terms in it and even imaginary terms, and that means the
quantum wave function is not a scalar like simple probability but a vector
with an intensity and a direction, and that means you can't just add up 2
independent probabilities to figure the probability both will happen the way
we usually do, and that means two very different wave functions can yield
the same probabilities, and that means we can't do things the way common
sense would dictate. And that's why the quantum world is so weird.

John K Clark       jonkc at att.net