Recurrence relation for harmonic oscillator wave functions

In summary, the conversation discusses a recurrence relation from a physics journal and the difficulty in proving it with the given form of radial wave functions. The issue of normalization and its relation to the validity of the recurrence relation is also raised. It is suggested that the orthogonality of the angular part of the wave functions may be the key to understanding this issue. The conversation also mentions an equivalent relation involving Laguerre polynomials and the importance of normalization in checking the recurrence relation.
  • #1
squareroot
76
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: 889
  • 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: 619
  • 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: 578
  • 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: 538
Last edited:
Physics news on Phys.org
  • #2
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.
 
  • #3
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.
 

1. What is a recurrence relation for harmonic oscillator wave functions?

A recurrence relation for harmonic oscillator wave functions is a mathematical equation that describes the relationship between successive terms in a sequence. In the context of quantum mechanics, it is used to determine the wave function of a particle in a harmonic oscillator potential.

2. How is a recurrence relation derived for harmonic oscillator wave functions?

A recurrence relation for harmonic oscillator wave functions can be derived using the Schrödinger equation, which describes the time evolution of a quantum system. By applying this equation to the harmonic oscillator potential and solving for the wave function, a recurrence relation can be obtained.

3. What is the significance of a recurrence relation for harmonic oscillator wave functions?

The recurrence relation for harmonic oscillator wave functions is significant because it allows us to determine the wave function for a particle in a potential that is commonly encountered in quantum mechanics. It also helps us understand the energy levels and probabilities associated with the system.

4. Can the recurrence relation be used for other types of potentials?

No, the recurrence relation for harmonic oscillator wave functions is specific to the harmonic oscillator potential and cannot be directly applied to other types of potentials. However, it can be modified and extended to describe systems with different potentials.

5. How is the recurrence relation used in practical applications?

The recurrence relation for harmonic oscillator wave functions is used in practical applications such as modeling molecular vibrations, analyzing the properties of condensed matter systems, and understanding the behavior of quantum mechanical systems in general. It is also used in numerical methods for solving the Schrödinger equation.

Similar threads

  • Advanced Physics Homework Help
Replies
16
Views
212
  • Advanced Physics Homework Help
Replies
1
Views
2K
  • Advanced Physics Homework Help
Replies
5
Views
1K
  • Advanced Physics Homework Help
Replies
5
Views
1K
  • Advanced Physics Homework Help
Replies
12
Views
4K
  • Advanced Physics Homework Help
Replies
3
Views
4K
  • Advanced Physics Homework Help
Replies
7
Views
3K
  • Advanced Physics Homework Help
Replies
4
Views
1K
  • Advanced Physics Homework Help
Replies
7
Views
2K
  • Quantum Physics
Replies
3
Views
939
Back
Top