- #1
Javier141241
- 3
- 0
Homework Statement
First sorry for the traduction mistakes.
Prove that any wave function of a particle in a 1 dimensional infinite double well of width a, returns to its original state in time T=4ma2/(πħ) .
Homework Equations
Ψ(x,t)=∑cnψn(x)·exp(-i·Ent/(ħ))
En=n2π2ħ2/(2ma2)
The Attempt at a Solution
I will explain my reasoning for a simpler case (combination of first two stationary states)
Ψ(x,t)=c1ψ1exp(-i·E1t/(ħ))+c2ψ2exp(-i·E2t/(ħ))
Since the global phase of Ψ doesn't matter ( |Ψ|2 ) you obtain the ω of oscillation taking common factor exp(-i·E1t/(ħ)) and obtaining ω=(E1-E2)/(ħ). Therefore for the wave function to return to the same state it was at t=0, t must be
t·(E1-E2)/(ħ)=2π
this leads to
t=4a2m/(2ħπ)·1/Q where Q its a term dependent of n
Since de statement says for any wave function and I get a similar result but depending of the Ψ in question, what I am missing? I wrote it for a combination of the two first stationary states, how would it be for a combination of n states? (since you can't take common factor the same way.)