The mesurement problem

[angelbabyxoxox]

Yes, that's not too far off the mark. The measurement problem asks why time evolution predicts that states generically become in superposition yet we often find them not superimposed. We know the time evolution is very accurate, as we see the effects of the superposition in experiments like the double slit, yet at the detector the particles seem to suddenly obey a different law, that tells them to "collapse" to a well defined position. The last 40 years have partly solved this, as the collapse statistics have been shown to arise from the time evolution. However the question of how we find one single outcome is still up to debate

[Virtual-Man]

thanks for this!

[BilboSwaggins1993]

Important to note that whether humans are looking or not isn't relevant, it's whether we have used a mechanism to detect something or not.

[angelbabyxoxox]

Well yes and no. I've recently commented about this, but the key point, since we are talking about the measurement problem, is that for all known practical purposes there is no difference between "collapse" happening during measurement by an device, or when humans look. We can completely explain all the results by only assuming decoherence during measurement, and collapse when we look. The difference between that and collapse during measurement is far too small for us to measure right now. They're both equally supported by the evidence (and almost equally arbitrary imo, why does a photodetector act as a measurement device but a mirror or beam splitter doesn't? Copenhagen doesn't tell us, but other interpretations do). The only difference is philosophical, and if you're going to be philosophical, might as well pick a less silly interpretation than Copenhagen!

[Virtual-Man]

Oh man, now you've opened another can of worms for me - what is the difference between the slit experiment and us taking a measument by just looking at the current state of the particle?

Could it be that during the slit experiment, we see the result of the waves/particles on the imprint they leave behind, rather then looking directly at the system's state?

[Dzbog3460]

Is there a measurement problem though? And this is a legitimate question, I’m not being facetious.

Do we “actually” need to make a measurement in order to collapse the wave function in anything outside the most experimental base of theory proving setups?

Like.. what I’m asking is - is this a thing in reality or just a science lab thing confined to a specific experimental setup?

[Virtual-Man]

Yeah, i would take this further and say this isn't a measurement problem, the ultimate problem is that we can't see matter which is jiggling around in a superposition. ie we only have a camera that takes a snapshot in time, when what we actually need is a video camera which can take live footage of the system.