Recent content by BacalhauGT

Thank you!

btw, can anyone recommend me a book for Fourier analysis with applications in physics? thank you

thank you. It was a distraction

Thank you. But please let me clarify one thing. I still don't get why the signs of the Fourier transformation are arbitrary. Can you explain me? So Fourier transform is ##f(t) = \frac{1}{2 \pi} \int_{-\infty}^{\infty} F(\omega) e^{i \omega t} d\omega## with ##F(\omega) =...

hey So Fourier transform is ##f(t) = \frac{1}{2 \pi} \int_{-\infty}^{\infty} F(\omega) e^{i \omega t} d\omega## with ##F(\omega) = \int_{-\infty}^{\infty} f(t) e^{-i \omega t} dt## Question 1 - The Fourier mode for the continuous case is ## \frac{1}{2 \pi} F(\omega) e^{i \omega t}##, is it...

When you say "The group velocity is the same as the velocity of the particle and can't be higher than the speed of light according to the equations of special relativity." you need quantum mechanics, right?

I Still don't understand why the group velocity has to be less than c but phase velocity not. Can you explain me this? Thank you :cry:

http://en.wikipedia.org/wiki/Ehrenfest_theorem hope this helps you edit: "expectations which are connected to classical mechanics." you should read "General example"

you have to start with something... its like why you start classic physics with F=const in one dimension

with complex numbers, derive exp(iwt) or something like that is just multiplying by iw (i=sqr(-1)). its easy. you can write the wave function as a sum of exponential terms (fourier t.) so it works for any wave.

each class of particles has a different dispersion relation http://en.wikipedia.org/wiki/Dispersion_relation the wave is a function of space and time and you can do the Fourier tranform. So we have (Quantum mechanics is that) for each f and waveleght: E=h f p = h/ wavelength A wave is...

there are "particlaves". everything propagates like a wave and interact changing its energy and momentum

With QM there's no "F=ma". waves interact with others and can change momentum p and energy E (that are related with wavelength or frequency). photon has momentum and energy it has (wavelength or frequency) as other particles. mass is just a parameter that defines a dispersion relation. for...

thank you. So, i will assume \psi = \sum_n \sum_m c_{nm} R^n Z^m . i just want the particular solution. So, with your method, i have (with GS eq): \sum_{n} \sum_{m} E_m C_n m (m-2) R^{m-2} Z^n + \sum_{n} \sum_{m} E_m C_n n (n-1) R^{2} Z^{n-2} then i change n-2 \rightarrow n'...

Thank you. i know the solution. i can see it in the books, but never how they solved and that's my problem. Whats really the name of the book you talked? ideal magnetohydrodynamics?