Thanks ChrisVer.
I'm not native, so a little difficult to understand that sentense. Sorry,but I ask in another words.
If A=\left(\begin{array}{cc} a & b \\ c & d \end{array}\right),
\sqrt{A}=\left(\begin{array}{cc} \sqrt{eigenvalue1} & 0 \\ 0 & \sqrt{eigenvalue2} \end{array}\right)?
I want to...
Hi, all
I'm reading peskin by myself.
I can't understand from eq(3.50) to eq(3.53).
i) What should I interpret \sqrt{p\cdot\sigma}?
I guess below, but I can't understand \sqrt{\;\;} of matrices.
\begin{eqnarray}
p\cdot\sigma=E \left(\begin{array}{cc} 1 & 0 \\ 0 & 1 \end{array}\right) -...