Griffiths quantum harmonic oscillator derivation

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Homework Help Overview

The discussion revolves around a step in Griffiths's derivation of the quantum harmonic oscillator, specifically focusing on the transition between equations in the context of recursion relations for large quantum numbers.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the validity of an approximate solution by substituting it into an equation. Questions arise about alternative derivation methods beyond the known solutions. There is also a suggestion that the structure of the recursion relation implies a factorial form in the solution.

Discussion Status

The discussion is active with participants questioning the derivation steps and exploring different approaches. Some guidance is offered regarding the expected form of the solution based on the recursion relation, but no consensus has been reached on the best method to derive the equations.

Contextual Notes

Participants are working within the constraints of Griffiths's framework and are considering the implications of approximations in their derivations. The exact solutions are acknowledged but not fully explored in the context of this discussion.

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Homework Statement



I am unsure as to a step in Griffiths's derivation of the quantum harmonic oscillator. In particular, I am wondering how he arrived at the equations at the top of the second attached photo, from the last equation (at the bottom) of the first photo (which is the recursion relation approximated for large j).

Any help?

Homework Equations


The Attempt at a Solution

 

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Substitute the approx. solution into the approx. equation. Is it satisfied?
 
Is there a way to derive the solutions besides via a fortiori means?
 
The could be some clever way, but since the exact solution is known, the approx. solution could equally have been obtained from it.

EDIT: it actually seems very simple: since for every "next" term we divide the previous by j/2, one should expect (j/2)! in the denominator, and c/(j/2)! should be fairly obvious as a possible solution.
 
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