Question on Intro QM pertaining to Harmonic Oscillator

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 1K views · last reply
warhammer
Messages
164
Reaction score
33
Homework Statement
Consider a system in a state
|ψ >=## frac{5/√50}*|φ0 > +frac{4/√50}*|φ1 > +frac{3/√50}*|φ2 >##
where |φ0 >, |φ1 > and |φ2 > are eigenstates of a harmonic oscillator
in ground, first and second excited state respectively.
(a) Find the average energy of this systemin the state |ψ >.
(b) What is the probability that |ψ > can be found in the state |φ1 >?
Relevant Equations
Avg Energy E=P(j)*E(j) (where E(n)=ℏw(n+0.5)
P(1)=## frac{|φ1|ψ>^2/<ψ|ψ > ##
Hi. I have attached a neatly done solution to the above question. I request someone to please check my solution and help me rectify any possible mistakes that I may have made.

Handwritten solution on lined paper: state |psi> = (5/sqrt50)|phi0> + (4/sqrt50)|phi1> + (3/sqrt50)|phi2>, normalisation check 25/50 + 16/50 + 9/50 = 1, average energy E = sum P_j E_j with E_j = hw(j+1/2), giving E = 118hw/100 = 1.18hw, and P_1(E) = |<phi1|psi>|^2 / <psi|psi> = 4/50.
 
Physics news on Phys.org
kuruman said:
Last line ##4^2=16##. Other than that it looks good.
Ah yes! Sorry for that silly error, I noticed that now.

And thank you tons for your prompt guidance 🙏🏻