"Observation" and the position of a particle in quantum mechanics ?

Question

When we observe /measure the actual position of a fundamental particle ,quantum mechanics tells us that an infinitesimally small time before that , that particle could have been farther away from that observed position ,than it could have travelled , even at the speed of light .(That is the positional time function isn't continuous).

Is this simply the (aberrational) consequence of the (wave) mathematics that has been developed to describe the quantum world ,or does it actually reflect physical reality ?

neb · Accepted Answer

The wave function IS continuous and represents a probability density of finding a particle at a particular position at a particular time. I have never liked the statements you sometimes read where they say a particle can be at multiple places at the same time. There is no evidence that is true.

There really isn’t a notion that the particle was a light year away but now it’s here where I just measured it. It means that there was a probability that it was a light year away - there is no real sense that it WAS a light year away and now it was here.

As for the ‘reality’ of the wave function, who knows? We think we know it’s non-local, e.g. in the double slit experiment it has a non-zero probability for both slits, but when we measure it through one, the probability for the other drops to zero (this type of thing applies even at galactic  levels). At this time, no one really understands what The wave function ‘collapse’ or the more generic state reduction of quantum mechanics means in terms of physical reality.

? · Answer

The conclusion there is we are not qualified to go to a Big Bang (Huge Boom) evolution.

"Observation" and the position of a particle in quantum mechanics ?

2 Answers