Classical uncertainty principle

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Discussion Overview

The discussion centers around the classical uncertainty principle, particularly its assumptions and applicability in measuring the pitch of a tone produced by a bowed violin string. Participants explore the relationship between the uncertainty principle and the measurement of frequency in both macro and micro contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • The original poster (OP) questions the assumptions of the classical uncertainty principle, suggesting it may not apply when measuring the pitch of a stable tone from a violin string.
  • Some participants argue that the uncertainty principle is not relevant to macro-sized objects like violin strings, asserting that it primarily concerns micro-level phenomena such as electrons.
  • One participant explains that the classical uncertainty principle is related to the Fourier transform and the definition of frequency, indicating that accurate pitch measurement requires longer observation times, which introduces uncertainty in frequency measurements.
  • Another participant expresses gratitude for the clarification regarding the relationship between the classical uncertainty principle and the Fourier transform.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the applicability of the classical uncertainty principle to macro-sized objects like violin strings, with some asserting it does not apply while others provide a technical explanation that connects it to frequency measurement.

Contextual Notes

There are unresolved assumptions regarding the definitions of frequency and the conditions under which the uncertainty principle is considered applicable. The discussion does not reach a consensus on the relevance of the principle to the specific case of violin strings.

Jeffrey Freed
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What assumptions underlie the classical uncertainty principle? The principle doesn't seem to apply when I want to know the precise pitch of a tone from a bowed violin string, since I can measure the duration (as precisely as I want) of the beats produced when I interfere it with a sine wave of known frequency. The violin string is fairly simple oscillator, not a completely unknown signal, and its frequency should be constant and stable. So, does the uncertainty principle apply only when you don't know the nature of the tone you're trying to determine the pitch of?
 
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Jeffrey Freed said:
What assumptions underlie the classical uncertainty principle? The principle doesn't seem to apply when I want to know the precise pitch of a tone from a bowed violin string, since I can measure the duration (as precisely as I want) of the beats produced when I interfere it with a sine wave of known frequency. The violin string is fairly simple oscillator, not a completely unknown signal, and its frequency should be constant and stable. So, does the uncertainty principle apply only when you don't know the nature of the tone you're trying to determine the pitch of?
The uncertainty principle has nothing to do with violin strings, as far as I know, partly because they are macro-sized objects and everything averages out. The HUP is about micro-level things (electrons, etc) taken individually.
 
phinds said:
The uncertainty principle has nothing to do with violin strings, as far as I know, partly because they are macro-sized objects and everything averages out. The HUP is about micro-level things (electrons, etc) taken individually.

The OP is referring to the classical (AKA mathematical) UP which basically is a consequence of how the Fourier transform (and our definition of frequency) work.
In this context all it means is that if you want to measure the pitch of the string with a good accuracy you need to measure for a long time and vice versa.
 
f95toli said:
The OP is referring to the classical (AKA mathematical) UP which basically is a consequence of how the Fourier transform (and our definition of frequency) work.
Ah. Thanks for giving me that understanding.
 

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