Recurrence relation for harmonic oscillator wave functions

Click For Summary
SUMMARY

The discussion centers on the recurrence relation for radial harmonic oscillator wave functions, specifically the form of Rnl as described in "Adv. in Physics" 1966 Nr.57 Vol 15. The user is attempting to validate this relation using Mathematica but encounters issues when the wave functions are not normalized. The consensus is that normalization is crucial for the recurrence relation to hold, as the orthogonality of wave functions is dependent on the normalization of the associated Laguerre polynomials. The user seeks clarity on why the relation fails without normalization.

PREREQUISITES
  • Understanding of radial harmonic oscillator wave functions
  • Familiarity with associated Laguerre polynomials
  • Knowledge of quantum mechanics principles, particularly wave function normalization
  • Proficiency in using Mathematica for mathematical validation
NEXT STEPS
  • Research the properties of associated Laguerre polynomials and their orthogonality
  • Explore the concept of wave function normalization in quantum mechanics
  • Learn how to implement recurrence relations in Mathematica
  • Investigate the implications of non-normalized wave functions in quantum mechanics
USEFUL FOR

Students and researchers in quantum mechanics, particularly those studying harmonic oscillators and wave function properties, as well as anyone utilizing Mathematica for mathematical proofs in physics.

squareroot
Messages
76
Reaction score
0
1. Homework Statement
I've been using a recurrence relation from "Adv. in Physics"1966 Nr.57 Vol 15 . The relation is :
Screen Shot 2017-11-18 at 11.35.40 AM.png

where Rnl are radial harmonic oscillator wave functions of form:

Screen Shot 2017-11-18 at 11.35.49 AM.png


The problem is that I can't prove the relation above with the form of Rnl given by the author(above). I've been trying to check this using Mathematica. The form in which I need to use this is the following:
Screen Shot 2017-11-18 at 11.43.28 AM.png

Screen Shot 2017-11-18 at 11.43.46 AM.png


Here, I use the Rnl's as radial wave-functions for neutrons and protons and multiply the first relation with Rprotonnl and integrate over spherical coordinates.(P.S the R's where noted by g's ).

My questions is why would a relation like this only hold if the R's(or g, respectively) are normalized? Should't this relation hold for any radial wavefunctions? Where does the normalization condition comes from?

The above relations are equivalent with let's say

$$ | \alpha \rangle = a |\beta \rangle + b|\gamma \rangle $$

and by multiplying with the bra ## | \alpha \rangle ## to the left one gets

$$ \langle \alpha | \alpha \rangle = a \langle \alpha | \beta \rangle + b \langle \alpha | \gamma \rangle $$

This is kind of my case above, but from my reasoning it should hold with no dependence on the normalization of the functions.

Thank you!

Homework Equations

The Attempt at a Solution

 

Attachments

  • Screen Shot 2017-11-18 at 11.35.40 AM.png
    Screen Shot 2017-11-18 at 11.35.40 AM.png
    4.7 KB · Views: 1,013
  • Screen Shot 2017-11-18 at 11.35.49 AM.png
    Screen Shot 2017-11-18 at 11.35.49 AM.png
    6.6 KB · Views: 761
  • Screen Shot 2017-11-18 at 11.43.28 AM.png
    Screen Shot 2017-11-18 at 11.43.28 AM.png
    7.7 KB · Views: 729
  • Screen Shot 2017-11-18 at 11.43.46 AM.png
    Screen Shot 2017-11-18 at 11.43.46 AM.png
    5.6 KB · Views: 708
Last edited:
Physics news on Phys.org
The associated Laguerre polynomials are not orthogonal for different values of ##l##. It is the angular part that ensures the orthogonality of the wave functions for different ##l##s.
 
I know that. My question was related to the fact that I can check the recurrence relation ONLY if I normalize the Rnl's first. If I try to use the relation with non-normalized wave-functions the relation doesn't hold and I can't understand why the relation doesn't hold. That recurrence relation, from my reasoning, should hold even for non-normalized functions.
 

Similar threads

Replies
1
Views
2K
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
0
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 3 ·
Replies
3
Views
5K
  • · Replies 5 ·
Replies
5
Views
3K