# I really need a definitive answer to the HUP/vacuum/pair production problem.

#### SeventhSigma

I hear different things all over the place and would like to clear up the confusion:

So I understand that, under HUP, position and momentum are things we can't know with arbitrary precision at the same time because momentum implies a measure of wavelength, but measuring wavelength means we're intrinsically introducing an uncertainty in position based on the probability function defined by that wave.

When we talk about the Casimir effect and particles popping in and out of existence (even in "empty space"), do we say we can really get something from nothing? Or do we say it's simply consistent with HUP?

Does pair production imply that the Big Bang could happen out of "nothing" via quantum fluctuations? Or does pair-production only make sense with respect to our universal framework as opposed to the creation of that framework itself?

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#### LostConjugate

I would not say it is something from nothing, rather just a statistical uncertainty. If you are uncertain where you left your keys and then you find them in the couch, it does not mean the keys were a manifestation of the couch.

#### tom.stoer

So I understand that, under HUP, position and momentum are things we can't know with arbitrary precision at the same time because momentum implies a measure of wavelength, but measuring wavelength means we're intrinsically introducing an uncertainty in position based on the probability function defined by that wave.
This is missleading. The HUP has nothing to do with measurement. It's not the measurement that introduces the uncertainty, but the uncertainty is an intrinsic mathematical property of the quantum state itself w/o any interaction or measurement.

#### DrChinese

Gold Member
Does pair production imply that the Big Bang could happen out of "nothing" via quantum fluctuations?
It is possible. I think the concept is that events like this happen from time to time.

No one really knows why there is something rather than nothing. Too big a question for my tiny brain.

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