Quantum Mechanical Simple Harmonics Question

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Discussion Overview

The discussion revolves around a quantum mechanical harmonic oscillator, specifically addressing the implications of a high quantum number on the system's behavior and the physical meaning of the average spacing between zeros of an eigenstate. The scope includes theoretical interpretations and the relationship between quantum mechanics and classical physics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant describes a harmonic oscillator with specific parameters and questions the physical representation of the average spacing between zeros of an eigenstate with a high quantum number.
  • Another participant suggests that the spacing refers to the distance between neighboring nodes of the wavefunction, where the probability of finding the particle is zero.
  • A different viewpoint proposes that with a high quantum number, the quantum model may resemble classical physics, potentially allowing for the neglect of Heisenberg's Uncertainty Principle.
  • In contrast, another participant argues that the Uncertainty Principle is not dependent on the quantum number but rather on the scale of the system, asserting that quantum methods are not applicable to macroscopic bodies.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of quantum mechanics to macroscopic systems and the implications of high quantum numbers. There is no consensus on whether the Uncertainty Principle can be disregarded in this context.

Contextual Notes

Participants highlight the limitations of applying quantum mechanics to macroscopic systems and the potential misinterpretation of quantum principles when dealing with large masses.

Ed Quanta
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So let us assume we have the following system. A harmonic oscillator consists of a mass 1g on a spring. Its frequency is 1 Hz and the masses passes through the equilibrium position with a velocity of 10cm/s.

I have already calculated that the magnitude of the quantum number (n = 7.6 x 10^27)

Now, what is meant by the average spacing between zeros of an eigenstate with such a quantum number? How would I calculate this, and what is this representing physically.

Thanks to all who have given this a look.
 
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With the spacing between two zero's of an eigenstate they most probably mean the distance between two neighbouring nodes (points where the wavefunction is zero). That's where you have zero probabability of finding the particle.

By the way. Since you have a mass of 1 g (!), are you dealing with a system of billions and billions of particles??
How can you say it passes the equilibrium position with a certain velocity. That's a violation of Heisenbergs principle.
 
I think because n is so great the quantum mechanical model approaches that of classical physics where Heisenberg's Uncertainty principle can be ignored?
 
No,The Uncertainty Principle has nothing to do when speaking of bodies whose size and hence mass are macroscopical...The quantum number "n" can be as big as u like,the microscopic/macroscopic scale of the problem is the issue.You can't approach by quantum mechanical methods a problem involving macroscopical bodies,because the results give no realistic meaning...
 

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