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- Thread starter bpm_vns19
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One thing to note. A pair of particles may have very sharply defined relative position (i.e. you can know they are almost exactly a distance x apart) but still not have a well defined absolute position but rather have a well defined total momentum.

I don't know if that is relevant to what you're thinking about. Why do you ask?

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You've heard of particle/wave duality, right? Well, when trying to measure these two properties on a particle, then where's the particle? Where's it's wave?

We don't know for sure. We are

Heisenberg's Uncertainty principle tries to answer the question, "How do we go about measuring a particle if it's a wave, also?" HUP was borne out of attempts at answering this question.

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You've heard of particle/wave duality, right? Well, when trying to measure these two properties on a particle, then where's the particle? Where's it's wave?

We don't know for sure. We areuncertain. We are uncertain of the particle's momentum if we try to measure its position. Likewise, if we try the obverse--try to measure where the particle is at (its position), then we don't know the particle's momentum. Hence, Heisenberg's Uncertainty principle.

Heisenberg's Uncertainty principle tries to answer the question, "How do we go about measuring a particle if it's a wave, also?" HUP was borne out of attempts at answering this question.

Heisenberg's UP is the statement about uncertainty it isn't "trying to answer the question 'How..."

Also the HUP isn't just about position and momentum but rather any two non-commuting observables such as x-component and z-component of angular momentum.

Again how are you trying to connect this to pair creation?

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is it a deterministic principle

Just to point out one important thing, the uncertainty principle properly refers to statistical measures, so in a sense it's a statistical principle. The uncertainties(delta X) in the HUP are standard deviations relating to means, not "absolute errors" relating to single samples of arbitrary confidence.

[tex]\sigma_x \sigma_p \geq \frac{\hbar}{2\pi} [/tex]

As you may know standard deviation is defined as an error window that is valid to a certain confidence level. (+/-[tex]\sigma[/tex] around mean covers ~68% of the samples.)

/Fredrik

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Heisenberg's UP is the statement about uncertainty it isn't "trying to answer the question 'How..."

Also the HUP isn't just about position and momentum but rather any two non-commuting observables such as x-component and z-component of angular momentum.

Again how are you trying to connect this to pair creation?

If you actually read my post, you would have noted that I said that the HUP "was

Furthermore, the HUP

To the OP, I think Fra answered your question adequately; HUP is strictly statistical in nature, as is most of QM.

HUP is not needed to determine the time at which the pair is created, since the created pair can be determined by the effect of the reaction that created the pair (eg, we know precisely when a correlated photon pair is created when we excite a calcium atom by an external lasing source). After particle creation, however, HUP must be applied to either particle--the reaction itself tells us nothing about the state of the correlated pair after they leave the apparatus they were created in.

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You've heard of particle/wave duality, right? Well, when trying to measure these two properties on a particle, then where's the particle? Where's it's wave?

We don't know for sure. We are uncertain. We are uncertain of the particle's momentum if we try to measure its position. Likewise, if we try the obverse--try to measure where the particle is at (its position), then we don't know the particle's momentum. Hence, Heisenberg's Uncertainty principle.

Heisenberg's uncertainty principle tries to answer the question, "How do we go about measuring a particle if it's a wave, also?" HUP was borne out of attempts at answering this question.

When you say that "when trying to measure these two properties on a particle, then where's the particle? Where's it's wave?" .How it is applicable in pair particle production ?There the particle is not alone . It is with its antiparticle .

How can be uncertainty principle then applied during pair particle production ?Can you give me a clear picture of that ??

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