How do we know uncertainty principal isnt ignorance?

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Discussion Overview

The discussion revolves around the Heisenberg Uncertainty Principle (HUP) and whether it reflects a fundamental limitation of nature or merely a limitation of our measurement capabilities. Participants explore the implications of the principle in the context of quantum mechanics, information theory, and the nature of physical observables.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that there may exist a method to measure speed and direction simultaneously, suggesting a potential link to information theory.
  • Others clarify that it is position and momentum that cannot both be known accurately at the same time, emphasizing that this is not merely a measurement issue but a fundamental aspect of the universe as described by the HUP.
  • A participant argues that the uncertainty principle is not about measurement disturbance but rather about the mathematical properties of non-commuting operators in quantum mechanics.
  • Another participant asserts that speed and direction can be measured simultaneously, contrasting this with the limitations posed by non-commuting observables like position and momentum.
  • There is a reference to previous discussions on the forum that have addressed misconceptions regarding the uncertainty principle, indicating ongoing debate about its interpretation.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the uncertainty principle, with some asserting it reflects a fundamental characteristic of quantum systems while others suggest it may be a result of our current measurement techniques. No consensus is reached regarding the interpretation of the principle.

Contextual Notes

Participants highlight the complexity of measuring non-commuting observables and the implications of quantum mechanics, but do not resolve the underlying assumptions or definitions that may influence their arguments.

acesuv
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what if there's a way to measure speed and direction at the same time and we haven't found it out yet? does it have to do with information theory?
 
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It is position and momentum which cannot both be known very accurately simultaneously.
 
acesuv said:
what if there's a way to measure speed and direction at the same time and we haven't found it out yet? does it have to do with information theory?
It is not a measurement problem, it's just the way the universe works. The fact that is not a measurement problem is inherent in the HUP

If you'd like to see more discussion, do a forum search. This canard has been debunked here many dozens of times.
 
acesuv said:
what if there's a way to measure speed and direction at the same time and we haven't found it out yet? does it have to do with information theory?

There's no problem with measuring speed and direction simultaneously. The uncertainty principle comes into play when we want to measure two things that in the mathematical formalism of quantum mechanics are represented by non-commuting operators. Speed and direction commute, so they're OK; but position and momentum, or angular momentum along different axes, and many others, are not.

You will find many explanations of the uncertainty principle that say that it's all about measuring one thing having to disturb another. These explanations are based on an erroneous understanding from seventy-five years ago. If you search this forum you will find a number of correct explanations based on what is now understood properly.

The basic issue is that I cannot set up a quantum system in such way that it has known and definite values for two non-commuting observables, call them A and B. I can set the system up so that it has a definite value for A, and then I can measure both A and B to as much precision as I like. However, if I repeat this experiment many times I will find that although I always get the same value for A, I get different values for B. The states in which A has a known value (called "eigenstates" of A) are all states that are not eigenstates of B, meaning that B can take on a range of values.
 

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