Quantum Harmonic Oscillator Differential Equation help

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Discussion Overview

The discussion revolves around the differential equation associated with the quantization of the harmonic oscillator, specifically the equation ψ'' + (2ε - y²)ψ = 0. Participants explore the solution to this equation as y approaches infinity and the implications of the resulting form of the solution.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant presents the differential equation and seeks clarification on the logical basis for the proposed solution form ψ = Ay^m e^{±y²/2}, questioning the reasoning behind the "guess" approach.
  • Another participant notes that the solutions to the equation can be expressed in terms of Modified Bessel functions or Parabolic Cylinder functions.
  • A third participant suggests using the Frobenius method for series expansion as a means to solve the ordinary differential equation (ODE).
  • The initial poster expresses understanding after receiving the responses.

Areas of Agreement / Disagreement

Participants provide various methods and forms of solutions, but there is no consensus on a single approach or reasoning for the solution form. Multiple perspectives on solving the differential equation remain present.

Contextual Notes

The discussion does not resolve the assumptions or conditions under which the proposed solutions are valid, nor does it clarify the specific limitations of the methods suggested.

cybla
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Hi, so i am looking at the quantization of the harmonic oscillator and i have the following equation...

ψ''+ (2ε-y^{2})ψ=0

I am letting y\rightarrow \infty to get...

ψ''- y^{2}ψ=0

It says the solution to this equation in the same limit is...

ψ= Ay^{m}e^{\pm y^{2}/2}

The positive possibility in the exponential is ignored since it is not in the physical Hilbert space. My question is how did they solve this differential equation? I have read a couple websites and it says that you just have to "guess" it... however, is there a logical way to why you would guess this? Thank you
 
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The solutions of this EDO are known in terms of Modified Bessel functions or alternately in terms of Parabolic Cylinder functions (in attachment)
 

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For the ODE just use the Frobenius method. Series expansion.
 
Okay i understand, thank you very much
 

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