Recent content by Final ansatz

Hi everyone, So, I've been trying to derive a general form for momentum Fourier transform of the polarizability \chi(\mathbf{r}t,\mathbf{r}'t') for a crystalline material, i.e. a material with a Bravais lattice. Since the material is not translationally invariant, it won't be enough with just...

Thanks for your reply and your kind welcome chiro. I agree that your suggestion is a good way to qualitatively understand the origin of the problems - and it's clear that the issue becomes significantly more complicated when \epsilon \neq 1. I would however still be very interested in any...

Hi everyone, I'm currently looking to solve an equation of the general form: \sqrt{x^2-y^2}+\sqrt{\epsilon x^2-y^2} = \beta. I'm interested in solving this equation for x assuming y>0, \epsilon>1 and \beta \in \mathbb{C}. By squaring the equation twice I can find four potential solutions of...

Thank you both a ton - your help is very much appreciated. Just couldn't get that bit right! Thanks alot, this has saved my week :).

Thanks for your reply Neumaier! Sadly, after having considered your suggestion for some time, I remain stuck with the same predicament as before. I must be confusing something basic. My intention with using \varrho for the density matrix and \rho for particle density operator, was that, in...

Hello everyone, I'm having some trouble, that I was hoping someone here could assist me with. I do hope that I have started the topic in an appropriate subforum - please redirect me otherwise. Specifically, I'm having a hard time understanding the matrix elements of the density matrix...