“a phenomenon which is impossible, absolutely impossible, to explain
in any classical way, and which has in it the heart of quantum mechanics.
In reality, it contains the only mystery.” The Bohr-Einstein debates
How can a particle go through both slits at once?
If I measured which one it went through, how
could interference occur between the two of them? Quantum mechanics
Waves of light are also particles...
and particles of matter are also waves!
QuickTime™ and a
are needed to see this picture.
MIT photo of atoms interfering!
(Relying on lasers and on
Bose-Einstein condensation!) Bohr-Einstein debates
for an unusual video recreating the debates... Wheeler & delayed choice Feynman’s Rules for interference
If two or more indistinguishable processes can lead to the
same final event (particle could go through either slit and
still get to the same spot on the screen), then add their complex
amplitudes and square, to find the probability:
2 ik1 ikL22
P = |A 1A 2| ≈ e + e | ≈ 1 + cos k(L -L1) 2
If multiple distinguishable processes occur, find the real
probability of each, and then add:
P = |A |2+ |A | ≈ |eikL1| + e ik2|2 ≈ 1
If there is any way – even in principle – to tell which process
occurred, then there can be no interference (if you knew
which slit the particle came from, you’d see a 1-slit pattern) ! What does it take to destroy