# Recent content by jhaber

1. ### Book on inequalities to help prepare for the Putnam exam

I'm reading Zee's QFT as self-study and have had trouble with the applications of group theory in Section 2. I'd love a book recommendation to fill in my gaps. I took algebra in the math department, but there groups were structures to distinguish from rings and such by definition, with no...
2. ### Classical limit from steepest descent

Ah, thanks. Good way of looking at it. As long as Lagrange's equation comes out of it, we win.
3. ### Pauli matrices: tau vs sigma

That's fine, thanks much. I know I'll have to read up more this chapter, as my group theory background is limited. I took an algebra course in math out of Herstein, where a group was just a set with a single operation that didn't necessarily commute, and such things as symmetry, matrices, and...
4. ### Pauli matrices: tau vs sigma

I'll have to think about that one. The in-text equations are quite consistent with both notations referring to the same set of three matrices. For example, the third is 1 0 0 -1 where you'll excuse me if I don't know Latex, so that gammma-0 = I 0 0 I works out to the direct...
5. ### Pauli matrices: tau vs sigma

In Zee's quantum theory text, introducing the Dirac equation, he states the gamma matrices as direct products of Pauli matrices. The statements involve the identity matrix, sigma matrices, and tau matrices. It took me a bit to realize that the latter were identical. I hadn't seen the tau...
6. ### Classical limit from steepest descent

I'm trying Zee's quantum field theory text as self-study (I'm years out of college) and about 100 pages into it. I can usually get something on the second or third reading. Oddly, one thing that keeps resisting me is quite early. In I.2, he says to apply an appendix on the method of steepest...