4-Fold Degeneracy of 14th Energy Level in Cubic Well

  • Thread starter Thread starter YoungEverest
  • Start date Start date
  • Tags Tags
    Degeneracy
AI Thread Summary
The discussion focuses on calculating the degeneracy of the 14th energy level in a cubic well, which is determined to be 4-fold degenerate with configurations (3,3,3), (5,1,1), (1,5,1), and (1,1,5). The participant notes that double degeneracy indicates symmetry related to 90-degree rotations, suggesting that symmetry is a significant aspect of this energy level. There is a clarification regarding the energy level numbering, emphasizing that the 14th energy level corresponds to the 14th highest value, not simply the sum of squares equaling 14. The confusion about the relationship between energy levels and their corresponding quantum numbers is highlighted. This discussion underscores the importance of understanding both degeneracy and the implications of symmetry in quantum mechanics.
YoungEverest
Messages
5
Reaction score
0

Homework Statement



In reference to the particle in an infinite, cubic well I have been asked to calculate the degeneracy of the 14th energy level and comment on its special nature.

2. The attempt at a solution
Notation: E_n = E (n_x , n_y , n_z)

E_14 = E(3,3,3)=E(5,1,1)=E(1,5,1)=E(1,1,5) and so is 4-fold degenerate.

Now, I know that a double degeneracy leads to a symmetry with respect to a 90 degree rotation. Am I along the right lines that symmetry is what is special about this case?

Thanks!
 
Physics news on Phys.org
Shouldn't the 14th energy level be the one where n_x^2+n_y^2+n_z^2 = 14?
 
The 14th energy level is the 14th highest energy value, if the energy level number was the product of 3 integers squared then you couldn't have a 1st, 2nd 4th etc. energy level. n_x^2+n_y^2+n_z^2 = 14 is the 6th energy level. :)
 
Thread 'Help with Time-Independent Perturbation Theory "Good" States Proof'
(Disclaimer: this is not a HW question. I am self-studying, and this felt like the type of question I've seen in this forum. If there is somewhere better for me to share this doubt, please let me know and I'll transfer it right away.) I am currently reviewing Chapter 7 of Introduction to QM by Griffiths. I have been stuck for an hour or so trying to understand the last paragraph of this proof (pls check the attached file). It claims that we can express Ψ_{γ}(0) as a linear combination of...
Back
Top