11 ms·
In the "delayed choice" experiment described, measuring the path of particles after they have traversed the slits forces their super position to collapse and yi
by mtuckah 10y ago
In the "delayed choice" experiment described, measuring the path of particles after they have traversed the slits forces their super position to collapse and yields no interference pattern on the detection screen. If that is the case, why doesn't the detection screen itself, which also measures the position of electrons, also force their super position to collapse? What is special about the detection screen as a measuring device?
- pif 10y ago> measuring the path of particles... > ... > the detection screen itself, which also measures the position of electrons, Alarm bells ringing around! Path and position are not the same thing, and that's quite an important distinction in quantum mechanics!
- dave_sullivan 10y agoFor those who don't know, it would be useful to explain "why" or include a reference.
- CuriouslyC 10y agoThink of measurement as the application of constraints. The slits are a form of weak measurement. This produces a loose constraint on the state of the electron - within the bounds of that constraint there are still many possible states in which it can exist. Depending on the type of measuring device, the constraint applied can be very tight, up to the limits of the uncertainty principle.
- dangirsh 10y agoThe screen DOES cause the superposition to collapse. It just does so after the electron was able to interfere with itself. This causes the probability distribution for the collapse to be different than it is in the presence of a detector at the slits (no interference).
- deleted 10y ago[deleted]