Recent content by tylerscott

I'm afraid I'm quite rusty in my chemistry here. So, Fe 3+ would be 3d5. However, I'm not sure where the 3+ for La is coming from (unless it's just because its a common oxidation state). How can one assume that the most common oxidation state is the right one to choose?

So Fe is 3d8. La is 5d3. On the right track?

So, La is 5d1, Fe is 3d6, As is 4p3, and O is 2p4. So Fe is close to half filling. But, so is As and O. So can we just say the bandstructure will compose of mostly Fe because of the half filling? Therefore, it is highly metallic and also the binding energy of the 3d6 should be much smaller?

Hi, I was hoping I could get some things cleared up. Recently my Solid State professor mentioned that we could simply, from the chemical formula, predict where the band crossings are going to be. For example, take LaFeAsO. Since La has a valency of +3, Fe of +3, As of -3, and O of -2, he...

Ah, thank you, I guess I need to work on keeping my indices separated. I appreciate all of the help (and patience!), JorisL. I think I have a better grasp of this now.

Ok, maybe. Let's see. So, let me know if this makes sense. Just working with the lowering operator: \hat{a}_{l} |\phi \rangle= \hat{a}_{l}N\sum_{k}|\epsilon _{k}\rangle = \hat{a}_{l}N\sum_{k}\hat{a}^{\dagger}_{k}|0\rangle From the anticommutation relations for fermions...

Ok, to be honest, the rigorous part of the proof is what is baffling me so much. A basis that spans our state will simply be the set of the \hat{a}^{\dagger}. But what next?

Well, I suppose due to orthogonality of the basis states, the\langle\Psi|\hat{a}_{k}^{\dagger}\hat{a}_{k}|\Psi\rangle would be \delta _{kl}\delta_{lk}? Since it seems the only nonzero states would be the point in which the creation operator creates a particle in the one that the annihilation...

Hi JoirsL, thank you for your response. I will first answer the ground state question, in the question above you can see that he defines the ground state as {\Psi}, so it appears to me as if we are supposed to be working within this state. The most general form of a state of a single...

Homework Statement Homework Equations and attempt at solution I think I got the ground state, which can be expressed as |\Psi \rangle = \prod_{k}^{N}\hat{a}_{k}^{\dagger} |0 \rangle . Then for the density matrix I used: \langle...

Ah! That's what I was looking for. So, how do you suggest integrating these over the surface?

The intensity falling on it will be constant, yes. But the angle at which the light hits will determine how much is transmitted through the material. This is what I'm trying to figure out.

Hello, I am currently working on a problem to calculate the light that makes it through a half circle. For example, say I put a cylinder out in the sun, where the intensity is known to be 1030 W/m^2. I would like to compute the intensity/energy/power that makes it into this. Now, given the...

I don't think I understand what that tells me about lambda... More insight please? Haha

Homework Statement A gauge transformation is defined so as to leave the fields invariant. The gauge transformations are such that \vec{A}=\vec{A'}+\nabla\Lambda and \Phi=\Phi'-\frac{\partial\Lambda}{\partial t}. Consider the Coulomb Gauge \nabla\cdot\vec{A}=0. Find out what properties the...