Solution to Schrodinger Equation

AI Thread Summary
The discussion revolves around solving Part B of a homework question related to the Schrödinger equation. The user is seeking assistance in finding a solution φ2(x, t) that satisfies the equation and matches the initial condition φ1(x, 0) = φ2(x, 0). A hint suggests using the superposition principle by expressing cos(k0x) as a sum of right and left moving plane waves. The user initially proposed a solution but doubts its validity and is looking for guidance on how to correctly apply the hint provided. The conversation emphasizes the importance of understanding the superposition principle in quantum mechanics.
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Homework Statement



I need Part B of this question

http://physics.wustl.edu/classes/FL2013/217/homework/ps03.pdf

Recall that the free particle Schr¨odinger equation,
i~

∂tψ(x, t) = −
~
2
2m

2
∂x2
ψ(x, t) (1)
has solutions of the “plane wave” form
ψk(x, t) = exp[ikx − iω(k)t] , (2)
where ω(k) = ~k
2/2m.
(a) (10 points)
Consider φ1(x, t) = cos(k0x − ω(k0)t). Show that φ1(x, t) is not a solution of the
Schr¨odinger equation, i.e. when plugged into both sides of the equation, identity
does not hold for all x and t as long as k0 6= 0.
(b) (10 points)
Find a solution φ2(x, t) to the Schr¨odingier equation that also satisfies φ1(x, 0) =
φ2(x, 0). (Hint: Write cos(k0x) as the sum of a right moving and a left moving
plane wave the way we did in class, and use the superposition principle. That
is, if you know the correct time dependence for each term in the sum, see class
notes, then you also know the correct time dependence of their sum.)

Homework Equations


The Attempt at a Solution



I thought the solution may be φ(x, t)=Ae(-k1x-ω1t)+Ae(-k2x-ω2t)
but I don't think it works out

Anyone have any idea how to solve Part B?

Thanks!
 
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Welcome to PF;
How did you go for part (a)?
You are provided with a hint for part (b), how did you apply it?
Why did you think your proposed solution may be correct, and what leads you to think that it doesn't work out after all?

How to type math equations on PF:
https://www.physicsforums.com/showpost.php?p=3977517&postcount=3

Schrödinger - you can write the umlaut in with the compose key.
 
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