Recent content by kknull

ok, I didn't know this fact. So the rules of composition of angular momentum work exactly with the spin hilbert space, but not for the orbital momentum, where we can add a relative momentum? Is there a formalization. maybe in some basic quantum mechanics book?

I can't understand, sorry :) we have 2 single particles, both with J=S=0. So L must be 0. if we compose the 2 system, we must have all quantum number=0 So J_f = L_f = S_f = 0. where is my error?

it says also that they are 2 scalar states, so S=0. Maybe it's just a notation error

page 88, just below eq 3.7. It clearly says that J=0 for both final particles

yes, but we have a composition of 2 J=0 states, so there shouldn't be any ways of conserving angular momentum, and this reaction shouldn't happen for this reason. However, this book: http://books.google.it/books?id=HNcQ_EiuTxcC&lpg=PP1&hl=it&pg=PA88#v=onepage&q&f=false says that the reaction...

well, J shouldn't be conserved in any ways in this situation, right? the composition of the 2 particles should give J_tot = 0 in any case

hi, I'm studying parity violation in particle physics.. I have this decay: 1+ ---> 0+ + 0+ in J^P notation. Why this process violate parity? All terms have positive parity. The parity of the products is just (+1)*(+1)*(-1)^l, so this means that the two scalar particles...

hi, I have 2 localized states in a hydrogenic atom.. we're in dipole approimation. I have to proof that <b| [p,V] | a> = <b| grad(V) |a> or equally: <b| V grad |a> = 0 (this is the dipole approximation in acceleration form) someone can help me? you can see...

ok, so is it a sort of jordan lemma? the integral along the semi circle is not 0, but it's the integral along C1 and C2. In other words: integral + C1 + C2 = residue of the pole integral = residue of the pole - C1 - C2 is it correct? thanks

sorry, the right pdf link is http://dl.dropbox.com/u/158338/fis/fetter2.pdf" also, I can't understand how the integral contour is chosen. thanks :)

Hi! I have to understand how this integral is evaluated (it is taken from Fetter - Quantum theory of many particle systems)(14.24): http://dl.dropbox.com/u/158338/fis/fetter.pdf" in particular, i don't know how the log brach cuts are defined.. as far as I know, log branch cuts can be...

ok, I have read some articles, including D&G. They're very interesting. In particular, in GR the gravity potential depends on the distance of the twins, so the astronaut can travel for many, many years, but then the effect of the gravity will be proportional. That was the answer. Btw, is...

ok, I have read some articles, including D&G. They're very interesting. In particular, in GR the gravity potential depends on the distance of the twins, so the astronaut can travel for many, many years, but then the effect of the gravity will be proportional. That was the answer. Btw, is D&G...

I think you're assuming always that the astronaut is travelling, so you're calculating traveller proper time (so the motion of the traveller) in function of Earth time... but I want to calculate Earth proper time in function of astronaut's time...

I don't think I have understand.. so the problem is that I cannot use a constant inertial frame in which the astronaut is at rest? can I use a frame in every time interval dt which is inertial and comoving with the astronaut and then study the proper time in Earth frame?