Recent content by Ylle

Hello... I didn't know which forum was the correct, so I hope it's ok to post it here. Basically I'm looking for a magazine I can subscribe to. Recently I've had one, but it really wasn't interesting after the first few I got. Besides that it was a "normal person" magazine, which means...

Thank you very much. I thought it was what I did to start with, but I just messed it up. But I got it now :) Thank you.

Hmmm... I think I may have it now. But what if the ladder operators are used on state |3> fx. ? At least the a+ operator. Then it would raise it to state 4, but that state isn't represented here, so will that just equal 0, or... ?

a_+ \lvert n\rangle = \sqrt{n+1} \lvert n+1\rangle and a_- \lvert n\rangle = \sqrt{n} \lvert n-1\rangle I think I did something like that, but as I said. I may have messed it up. But I was right with the thought I had ? I just need to redo the math perhaps ?

Homework Statement Hello everyone... I'm kinda stuck with a problem I'm trying to do. The problem states: Express the operator \hat{x} by the ladder operators a_{+} and a_{-}, and determine the mean of the position \left\langle x \right\rangle in the state \left| \psi \right\rangle.Homework...

I think so... There is given a hint that I should look how to commutate the spin matrices, where fx. [Sx, Sy] = ihSz (i = complex number, h = h-bar) - if I remember correctly.

Homework Statement Hi... I'm having something about the Interaction/Dirac picture. The equation of motion, for an observable A that doesn't depend on time in the Schrödinger picture, is given by: \[i\hbar \frac{d{{A}_{I}}}{dt}=\left[ {{A}_{I}},{{H}_{0}} \right]\] where...

Well, thank you :) Didn't know it was that easy.

Ahhh... It said: IS the Fock states eigenstates for the operators, doh... So when I use the operators on the Fock state, they are not eigenstates because of the |n-1> and |n+1> at the end, which should have been just |n> in each case, or am I way off ?

Homework Statement I have to show that the Fock states are eigenstates for the operators {{\hat{a}}^{\dagger }} and/or {\hat{a}} And I'm not totally sure how to show this. Homework Equations ? The Attempt at a Solution I know that if I use the operators on a random Fock...

Argh, ofc... That's much easier :) Thank you :)

So instead of the above it's: I=\int_{0}^{R}{J}\left( 2\pi R \right)dR-\int_{0}^{R/2}{J}\left( 2\pi R \right)dR It gives the correct answer, but I don't know if that is what you meant ?

Well, that is what I've written in the "Relevant equations" section.

Homework Statement I got this problem (Sectional image of a cylinder): http://img715.imageshack.us/img715/3448/cylinder.jpg Besides that I know that the cylindrical conductor is infinite long, and the same is the cavity. And through the conducting material there is a current density that is...

Ok, now I'm with :) Thank you.