Simple harmonic oscillator Hamiltonian

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 replies · 3K views
docnet
Messages
796
Reaction score
487
Homework Statement
please see below
Relevant Equations
please see below
Screen Shot 2021-02-11 at 3.33.10 PM.png

We show by working backwards
$$\hbar w \Big(a^{\dagger}a+\frac{1}{2}\Big)=\hbar w \Big(\frac{mw}{2\hbar}(\hat{x}+\frac{i}{mw}\hat{p})(\hat{x}-\frac{i}{mw}\hat{p})+\frac{1}{2}\Big)$$
$$=\Big(\frac{mw^2}{2}(\hat{x}^2+\frac{i}{mw}[\hat{p},\hat{x}]+\frac{\hat{p}^2}{m^2w^2})+\frac{1}{2}\Big)=\frac{1}{2}mw^2\hat{x}^2-\frac{\hbar w}{2}+\frac{\hat{p}^2}{2m}+\frac{\hbar w}{2}$$
$$=\frac{1}{2}mw^2\hat{x}^2+\frac{\hat{p}^2}{2m}=\hat{H}$$
This shows the time-independent Schrödinger equation for the simple harmonic oscillator can be written as
$$\hbar w \Big(a^{\dagger}a+\frac{1}{2}\Big)|\psi>=E_n|\psi>$$
 
Last edited:
Reply
  • Like
Likes   Reactions: Delta2 and PeroK
on Phys.org