Recent content by sunkesheng

:smile: get it ,there is a change which is important and very simple ,and it is until now that i realized it : \sigma^{\mu}_{\alpha\beta}=\sigma^{\mu}^{T}_{\beta\alpha} thanks a lot!

that is right,and peskin had learned from weinberge,hh

many thanks .it is my fault,i don`t express my question clearly,so sigma is the 2*2 pauli matrix ,but subscript of the front two sigma matrixs in the first row is \beta ,in the second it changes to \delta,that is what i puzzled.

i see ,but why the \singma[\nu]\sigma[\lambta] in the first row can be write to that in the second row,:confused:

thanks ，i found it in weinberge`s book vol.1

peskin`s introduction to QFT [3.82],do not know what he had done to the underline

i can see the mean of "[]" in the first row,it is the anticommunicater between \gamma{\mu} and \gamma{\nu}, but what it mean in the second row and the third? thanks

i find a similar topic,maybe it is helpfull https://www.physicsforums.com/showthread.php?t=273600"

thanks a lot,but i still cannot understand it ,because the book just gives the equation ,where can i find a detailed derivation?

hi ,i see from a book su(2) has the form U\left(\hat{n},\omega\right)=1cos\frac{\omega}{2}-i\sigmasin\frac{\omega}{2} in getting the relation with so(3),why we choose \frac{\omega}{2},how about changing for \omega? thank you