Double Slit Experiment With Detectors

[StevieTNZ]

Hi there,

I've been told even with detectors behind two slits detecting if a particle comes through, that doesn't exactly mean that the quantum system is now in a mixed-state (for example, the quantum eraser experiment of Scully).

How would we be able to differentiate between whether the system has collapsed or not at the screen? Even though it looks like a scatter pattern, wouldn't it really be made up of a fringe + anti-fringe interference pattern? Would we need to do some form of erasure on the detectors to determine whether the particle had gone through one slit or not? Say for example, half the time we go to detector 1 and reset it, then to detector 2 and reset it. And the other half, detector 2 and reset it, then detector 1 and reset it.

 

[Drakkith]

What do you mean by "collapsed at the screen"?

 

[StevieTNZ]

Whether it had gone through one slit or both.

 

[Drakkith]

Over time the pattern of events will show either interference or no interference. We cannot tell on an individual particle basis whether it was detected in one slit or not, at least not in this method. (By only looking at the screen that is. If you look at the detectors at the slits it will be obvious)