- #1
unscientific
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Homework Statement
Part (a): Particle originally sits in well V(x) = 0 for 0 < x < a, V = ∞ elsewhere. The well suddenly doubles in length to 2a. What's the probability of the particle staying in its ground state?
Part (b): What is the duration of time that the change occur, for the particle to most likely remain in ground state?
Homework Equations
The Attempt at a Solution
Part (a)
For a well of length a, eigenfunction is:
[tex]u = \sqrt{\frac{2}{a}} sin \left(\frac{\pi x}{a}\right) [/tex]
For a well of length 2a, eigenfunction is:
[tex]v = \frac{1}{\sqrt a} sin \left(\frac{\pi x}{2a}\right) [/tex]
For probability amplitude, overlap these 2:
[tex] \frac{1}{2} \frac{\sqrt 2}{a} \int_0^{2a} 2 sin (\frac{\pi x}{a}) sin (\frac{\pi x}{2a}) dx [/tex]
[tex]\frac{1}{2} \frac{\sqrt 2}{a} \int_0^{2a} cos (\frac{3\pi x}{2a}) - cos (\frac{\pi x}{2a}) dx[/tex]
which goes to zero.
Part (b)
Am I supposed to use time evolution: ## |\psi_t> = U^{-i\frac{E}{\hbar}t}## ? Doesn't seem to help..