Student Friendly Introduction to QFT · Problem 31

Vectors: Spin 1 Fields

Physics — QFT · gamma-matrix-contraction

Problem

Using the anti-commutation relations (4-157) and the definition

\gamma_\mu = g_{\mu\nu}\gamma^\nu

, prove that

\gamma_\mu \gamma^\mu = 4I

, where

I

is the 4X4 identity matrix in spinor space.