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by chadcmulligan
2210 days ago
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Many thanks, I don't doubt its how things are, almost thought I had a handle on it :-). Will have to take a year or two sometime and do some reading, don't think I really understand what a 'collapse' is, amongst many other things. Edit: is a collapse a measurement? Before the measurement all the possible states are there, then a measurement occurs, and we then know the result (within uncertainty). |
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The collapse is a measurement. It is also the instantaneous moment that a particle such as a photon goes from being a wave-like to being particle-like. In many ways it is just a name given to the phenomenon that we know occurs - that particles act as waves until we need them to be more "real" so to speak.
In Copenhagen, the "wavefunction collapse" is when the particle "picks a spot to land" inside of its wave. The spots it is likely to land are defined by the peaks and valleys of the wave.
Imagine liquid waves in the ocean again. They go up and down with fairly predictable heights of waves. Wavefunction collapse is when those waves decide to collapse into a small rock instead. But where should the small rock wind up? Well the highest wave of course. The wavefunction collapse is when the decision occurs to _place_ the rock; when the universe says "throw a dart somewhere along this path of likely positions".
That's a bit more metaphorical and philosophical but maybe it puts it into perspective a bit better? To be honest, I don't understand it very well and certainly couldn't tell you why it happens from more basic principles. This is part of the reason there are competing interpretations which is that even Copenhagen style wavefunction collapse _feels_ weird.