# Intro Quantum subscripts and operators, can someone please clarify these in this prob

1. Dec 31, 2012

### faceforest

I'm working with flow equations right now and have been stuck on this one part (I'm re-doing the work of one of my professors).

I figured it would just be way easier to take a picture and post it rather than type up all the bra's and ket's and subscripts, etc. So here(http://i.imgur.com/RYY6Y.jpg) it is.

I'm getting lost when the derivative of Vij is taken. I tried to work back-words from it and get lost with trying to commute it to my derivative. This is most likely because I'm confused about the subscripts. As for the part when i={a,b} for T, I think I get what is going on but again, slightly confused as to why the z-pauli matrix was chosen with the Identity matrix.