# Question in Rae Chapter 4

1. Nov 4, 2006

### swain1

A particle moving in a 1-D box subject to a potential that is zero in the region and infinite at the walls and elsewhere.

(a) Determine the possible results of the measurement of the energy of this system and their relative probabilities. (b) What are the possible forms of the wave function immediately after such a measurement? (c) If the energy is immediately re-measured, what now will be the relative probabilities of the possible outcomes?

For this question I have the wavefunction at a paticular time and also the energy eigenvalues and eigenfunction. I understand the maths involved but I am struggling with working out what I have to do. I would be grateful of any help. Thanks

2. Nov 4, 2006

### dimachka

well if you have the energy eigenvalues, you are done with part a, if you have the wavefunction you are done with part b, so it seems like you are well on your way. Part c wants you to realize that in quantum mechanics, a measurement collapses the wave function, google "quantum mechanics wavefunction collapse".

3. Nov 5, 2006

Regards
marlon

4. Nov 5, 2006

### swain1

Thats really the problem I have is getting started. What I have tried is to work out the overlap integral of my wavefunction and the eigenfunction but I just have a horrible integration that I can't do and I don't know if I am going about it in the right way?

5. Nov 13, 2006

### Colom

im trying to do that same exercise, but i dont know how to start, im really having trouble with this one, could anyone give me a hand?