3 ms·

> even if that observation should not disturb the particle's motion this claim has always frustrated me can someone who agrees with it defend it from first pr

• XorNot 10y ago
  If a particle is strictly a point like entity then we expect it to be localised. In space. And that means an observation which probes somewhere it isn't shouldn't affect it. However, single photon double slit experiments don't show this - the particles act as though they are interfering with each other even though a photon detector will show photons arriving one at a time, at a rate which shows only one photon could have been traversing the apparatus at a time.
  • justifier 10y ago
    maybe I should have included the whole quote, but this is regarding the double slit experiment stead delayed choice quantum eraser experiments, where you measure over here but seem to affect over there > If we place a detector inside or just behind one slit, we can find out whether any given particle goes through it or not. In that case, however, the interference vanishes. Simply by observing a particle's path – even if that observation should not disturb the particle's motion – we change the outcome. when we place an observer at one of the slits we lose the previously ambiguous diffraction and instead get a clump pattern, but we are definitely probing where it is