Recent content by NewGuy

I'm looking for a book that describes Quantum Field Theory from a group theory approach for mathematical physicists (with emphasis on the physics part). Ideally I want it to first describe and define groups, representations and irreducible representations. The more rigorous the math, the better...

If you would that I would be very grateful :)

I'm trying to prove that the helicity operator \pmb{\sigma}\cdot\pmb{\hat{p}} is invariant under rotations. I found in Sakurai: Modern Quantum Mechanics page 166 that the Pauli matrices are invariant under rotations. Clearly that is sufficient for the helicity operator to be invariant under...

I have need to calculate the residues of some functions of the form \frac{f(x)}{p(x)} where p(x) is a polynomial. To be more specific I have already calculated the 2 residues of \frac{1}{x^2+a^2}. That one was quite easy. Now I'm asked to calculate the residues of...

I ran into a problem reading Sakurais book about advanced quantum mechanics. I understand what a spherical tensor operator is, it's just an odd number of operators that transform in a nice way under rotation (or equivalently has some nice commutation relations with angular momentum). Sakurai...

I'm having a course in advanced quantum mechanics, and we're using the book by Sakurai. In his definition of angular momentum he argues from what the classical generator of angular momentum is, and such he defines the generator for infitesimal rotations as...

I'm an undergraduate in physics, I'm on my 2nd year. I have to write this assignment about the Higgs particle and gauge theory. There are quite some things that are unclear to me however. Since I'm only on my second year I don't know a lot of deep math like group theory, just basic stuff. I know...

This is a nice thing indeed! If we have that the curve integral around the singularity is 2 pi that is true for all closed paths around the singularity? I suspect that it is a requirement that curl(F) is zero everywhere along the path? Does the same thing apply to R^3? Regarding the square...

I have a question regarding conservative vectorfields and singularities. Suppose we have a vectorfield who is defined everywhere in R^2 except at the origin where it has a singularity, and suppose it's curl is zero. We then have that it is conservative in every open, simply connected subset in...