# Polariations vectors

by Lapidus
Tags: polariations, vectors
 P: 283 In QFT, for the massive vector particles we have in the rest frame the following polarization vectors. $\epsilon^{a}_{\mu}$ where a = 1,2,3 with $\epsilon^{1}_{\mu}$ = (0,1,0,0) $\epsilon^{2}_{\mu}$ = (0,0,1,0) $\epsilon^{3}_{\mu}$ = (0,0,0,1) I do not understand the indices, a and $\mu$ and how the relate? What would $\epsilon^{1}_{1}$ be in the given rest frame? What happens when the frame is boosted? thanks