Recent content by clumps tim

Ah great, thank you very much, I almost got it on the track now, this is $$ \int_{0}^{\infty} x^3 e^{-(n+1)x} dx = 6 (n+1)^{-4}$$ can you just tell me a little about how to evaluate the summation of $$\sum \frac{1}{(n+1)^4}$$ though, I think I forgot this evaluation. thanks in advance

HI people, I was trying to derive the stefan-boltzman law from the planc's formula, I kind of got stuck with an integral $$ \int_{0}^{\infty} \frac{x^3}{e^x -1} dx $$ I tried simplifying it with $$ \int_{0}^{\infty} x^3 e^{-x} \sum_{n=0}^{\infty} e^{-nx} dx $$ Now I don't know what to do...

hi , i need some help in this integral e^(-bx^2) d^2/dx^2 (e^(-bx^2)) dx from - to + infinityI tried differentiating e^(-bx^2) twice and it came up weird , is there any other way to do it ?

Hi, I am going for the same institute as you mentioned. I don;t know my scores yet but I wish you get into the program with your good background. let me know if you have any contact with the faculty members.

Yes that was in my 1 hour midterm . I thought the instructor was going to test our physics knowledge and not scare us with tricky integrals. anyway thanks for your suggestions. I will take a look at Boas .

I remember one, I wanted to do it by integration by parts and then I see its not doable that way. integral ( r^2 e^(-r/a) sin(kr)) dr I t must be pretty easy that I misses due to my ignorance

As a physics major, I felt devastated today when I had to face the toughest integrals in my life for advanced quantum mech course. I am really embarrassed I did bot learn integration properly. please suggest me a good book that will help me excel in sort of integraion I will face for QM and...

Hi, I need a beginner's book to study gravitational waves by myself. I am an undergrad physics major and just took my GR course. A beginner's book on GR will also help me lot. please suggest

Hi, I am going to take PGRE this 25th October. as my country does not arrange it, I need to fly to another, so I need to know the materials I need to bring in the hall. I have my GRE admision ticket printed. what else should I carry with me? pencil, paper, food ?

Hi, I have a simple harmonic oscillation problem whose Green function is given by $$\Bigl[\frac {d^2}{dt^2}+ \omega_{0}^{2}\Bigl] G(t, t') = \delta(t-t')$$ Now I found out the Fourier transform of $G(t, t')$ to be $$G(\omega)= \frac{1}{2\pi} \frac{1}{\omega_{0}^{2}-\omega^2}$$ which has poles...

hi, I need some reading materials on green function for SHO. my instructor provided a GF frequency and wanted us to find the deformation of poles , boundary conditions for the function. I need to know which mathematical background should I have to solve this. any useful material suggestion will...

HI, I have been going through dirac's paper on quantized singularities in the electromagnetic field and there he referred to a problem of negative kinetic energy of electron, what does it mean? I am going to make a presentation on magnetic monopole next month so I need an explanatory answer...

thank you very much, I am perusing the papers. can you give me some suggestions on how to work on an undergrad paper ?

Hi , I am having a presentation on QM charge monopole system at the end of November as a requirement for my course. I need some good resource on it to dig in as my instructor left it in our hand. so kindly suggest me some good things to start on . for your information, I am in final year of...

Hi , I need a good book or lecture on quantum hall effect. my supervisor wants me to find the Hamiltonian for the Qunatum hall effect, he want me to find this from this relation if it looks like a 2nd order differential of harmonic oscillation. can you please guide me doing this? $$H=...