Consider the three-dimensional harmonic oscillator, for which the potential is
V(r)=21mω2r2. (4.215)
(a) Show that separation of variables in cartesian coordinates turns this into three one-dimensional oscillators, and exploit your knowledge of the latter to determine the allowed energies. Answer:
En=(n+23)ℏω. (4.216)
(b) Determine the degeneracy d(n) of En.