That Heisenberg Uncertainity Principle

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SUMMARY

The Heisenberg Uncertainty Principle is a statistical statement regarding the outcomes of measurements on a large number of similarly prepared systems, rather than a direct assertion about measurement uncertainty. Specifically, it indicates that if the position of a particle is measured with high accuracy, the momentum will exhibit a corresponding uncertainty, quantified as approximately h/2π. This principle is derived from the Cauchy-Schwarz inequality, which relates the expectation values of two observables, confirming that the product of these values is constrained by the commutator of the observables. The principle emphasizes the inherent limitations in predicting simultaneous values of position and momentum.

PREREQUISITES
  • Understanding of quantum mechanics fundamentals
  • Familiarity with the concepts of observables and commutators
  • Knowledge of statistical mechanics
  • Basic grasp of the Cauchy-Schwarz inequality
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  • Study the mathematical derivation of the Heisenberg Uncertainty Principle
  • Explore the implications of the Cauchy-Schwarz inequality in quantum mechanics
  • Learn about the role of commutators in quantum theory
  • Investigate the statistical interpretation of quantum measurements
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Physicists, quantum mechanics students, and researchers interested in the foundational principles of quantum theory and measurement uncertainty.

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Does the Heisenberg Uncertainity Principle mean:
1) If a particle is confined within a length x then it must jiggle around with a momentum given by p ~ h/2x PI

OR

2) If we measure the position of a particle to an accuracy of x then its momentum will be uncertain by ~ h/2x PI
 
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It means neither.

It says if you have a large number of similarly prepared systems, measure the position on half of them, and momentum on the other half, then the variance of those results will be as per the uncertainly relations.

It is not a statement about uncertainly of measurement - you can measure momentum or position as accurately as you like - its a statistical statement about the outcomes of a large number of measurements.

Thanks
Bill
 
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The more general version of the uncertainty principle, derived by the cauchy schwarz inequality states thet the product of the expectation values of two observables is greater than or equivaleent to half the expectation value of the commutators of the observables. The Heisenberg uncertainty principle just uses the fact that the commutator of X the position and P the momentum is -ih(bar) and substitiues that in the equation. The equations you wrote are just reformations of the principle
 

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