Hesienburg Uncertainity Principal

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Discussion Overview

The discussion revolves around the Heisenberg Uncertainty Principle (HUP) and its implications for the measurement of position and momentum in quantum mechanics. Participants explore the nature of uncertainty, the limits of measurement, and the philosophical implications of wave-particle duality.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that quantum objects do not possess simultaneously well-defined values for position (Δx) and momentum (Δp), suggesting that this is not merely a knowledge issue.
  • Others argue that there appears to be no lower limit to uncertainty for the measurement of a single observable, raising the question of whether Δx or Δp can ever be zero.
  • One participant expresses the belief that if Δx or Δp were zero, it would violate the uncertainty principle.
  • Another participant suggests that both Δx and Δp cannot be zero due to implications for quantum vacuum zero-point energy.
  • Some participants clarify that while Δx or Δp can be arbitrarily close to zero, they cannot be exactly zero, as this would lead to non-normalizable states that cannot be interpreted as probabilities in quantum mechanics.
  • There is a mention of mathematical constructs such as delta distributions and plane waves, which are not physically realizable but are used for mathematical convenience in quantum mechanics.

Areas of Agreement / Disagreement

Participants express differing views on whether Δx or Δp can be zero, with some asserting it is impossible due to the principles of quantum mechanics, while others suggest that they can approach zero but not reach it. The discussion remains unresolved regarding the implications of these positions.

Contextual Notes

Limitations include the dependence on interpretations of quantum mechanics and the mathematical frameworks used, which may not fully capture the physical realities being discussed.

Who May Find This Useful

This discussion may be of interest to those studying quantum mechanics, philosophy of science, or anyone curious about the implications of the Heisenberg Uncertainty Principle.

Tigersharkmks
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As per Heinsburg uncertainity principle, Δx*Δp≈h. It means we cannot actually measure simentenously both position and momentum of the matter. They reason out this because of wave-particle duality of matter. So my question is wheather we dont't know the exact x and p of matter under consideration or the matter itself deosnt know it what is its position or momentum. To make my question more clear, does uncertainity means our knowledge in limited but nature is absolute or nature itself doesn't know in which state it is?
Also can Δx or Δp be ever zero. I'm asking this because if this is not the case, then my interpretation that position of say electron is then not localised but spread, so does this give rise to wave like nature of electron (because wave are also spread). Correct me if I am wrong.
Thanks:
 
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Tigersharkmks said:
As per Heinsburg uncertainity principle, Δx*Δp≈h. It means we cannot actually measure simentenously both position and momentum of the matter. They reason out this because of wave-particle duality of matter. So my question is wheather we dont't know the exact x and p of matter under consideration or the matter itself deosnt know it what is its position or momentum. To make my question more clear, does uncertainity means our knowledge in limited but nature is absolute or nature itself doesn't know in which state it is?
Also can Δx or Δp be ever zero. I'm asking this because if this is not the case, then my interpretation that position of say electron is then not localised but spread, so does this give rise to wave like nature of electron (because wave are also spread). Correct me if I am wrong.
Thanks:

1. As far as can be determined scientifically today, it appears that quantum objects do not possesses simultaneously well defined values for non-commuting operators. So X and P are not both defined, and it is not an issue of knowledge.

2. There appears to be no lower limit to uncertainty for the measurement of a single observable. So Δx or Δp can be zero.
 
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DrChinese said:
2. There appears to be no lower limit to uncertainty for the measurement of a single observable. So Δx or Δp can be zero.

I would have thought that the uncertainty of Δx or Δp can't be zero, as it would violate the principle.
 
This thread sets new standards when it comes to spelling uncertainty. Please, my eyes are bleeding.
 
LOL :smile: Thank god it wasn't Principal Hindenburg ... ouch my stomach huirts


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StevieTNZ said:
I would have thought that the uncertainty of Δx or Δp can't be zero, as it would violate the principle.

Maybe your missing or? Afaik, both Δx and Δp can't be zero, as this would violate quantum vacuum zero-point energy (i.e. the energy of its ground state).

600px-Harmoszi_nullpunkt.png


The energy of the quantum ground state is E_0 = \hbar \omega / 2

Where \omega is the angular frequency at which the system oscillates and \hbar is Planck's constant h dived by 2\pi, which is an extremely tiny number ≈ 1.05457×10−34 J s.
 
As long as the HUP is respected, Δx or Δp can be arbitrarily close to zero but not exactly zero.

This is because the corresponding states (delta distributions and plane waves) are not normalizable which means that we cannot interpret |ψ|² as a probability (density) as needed for QM.
 
kith said:
As long as the HUP is respected, Δx or Δp can be arbitrarily close to zero but not exactly zero.This is because the corresponding states (delta distributions and plane waves) are not normalizable which means that we cannot interpret |ψ|² as a probability (density) as needed for QM.

Indeed such states are not physically realizable, and are not square integrable which they must be to be physical.

But they are introduced for mathematical convenience being part of the Rigged Hilbert space formalism QM really depends on. The test functions of the space are the physically realizable states, things like the Dirac delta function are linear functions defined on those states to make the math easier eg so things like position operators have eigenvectors.

Thanks
Bill
 
This is the greatest thread ever
 

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