Recent content by Hypersquare

Sorry I meant in the well, where the potential is zero.

Hi there, Im confused by something that came up in my quantum mechanics lecture. The lecturer posed us a question. What result do I get for a measurement of momentum if I have already measured the energy. I assumed after measuring energy that the system would be left in an energy...

I got it by doing: \vec{F} . \hat{n} = \frac{\vec{r}}{r^{3}} .\frac{\vec{r}}{r} = \frac{1}{r^{4}} I don't see what is wrong with that.

I got \vec{f}.\hat{n} as 1/r^{4} not 1/r^{2} as they got. What have I done wrong?

Thank you Ivy. Very helpful.

I also don't quite get why the is unit vector is not just r hat

Sorry that's supposed to be n hat and the vector r, I am a latex noob.

I was looking at this example: http://keep2.sjfc.edu/faculty/kgreen/vector/block3/flux/node10.html and was confused between the difference between \hat{}n and \vec{}r Why is the original vector field not given in terms of a unit vector? And what difference does this make? Thanks :)

Thanks fo the response Kloptok! No such information is given. I am just told that the total width of delta 1232 resonance i 118 Mev.

Hey now! I have just calculated the lifetime of a resonance state using its total width. I want to work out which force this decay is due to. How would one go about doing this? Thanks

Ah ok thanks. Turns out the analogy of hitting the rewind button on a video of the particles motion is more useful than Id thought.

Hi all, I was just pondering why spin is odd under time reversal. I am trying to get my head around CPT invariance and am failing to find good material online. Thanks

Thanks TSny. I did both of those and it seems that BR Martin was correct! My energy comes out negative and his positive. The solutions agree on application of the momentum operator though. This means that I have misunderstood something entirely then. I am not sure what though.

Hi there! I have tried to apply time reversal (which makes t -> -t) to a free particle wavefunction: Exp[i(p.r-Et)/\hbar] and got: Exp[-i(p.r-Et)/\hbar] I got this by flipping the sign of p since it has a d/dt part, and flipping the t in the Et part. However I think this is wrong...