- #1
spaghetti3451
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Physical polarization vectors are transverse, ##p\cdot{\epsilon}=0##, where ##p## is the momentum of a photon and ##\epsilon## is a polarization vector.
Physical polarization vectors are unchanged under a gauge transformation ##\epsilon + a\cdot{p}=\epsilon##, where ##a## is some arbitrary constant.
1. Why are physical polarization vectors transverse?
2. Why is ##p\cdot{\epsilon}=0## the condition for the transverseness of ##\epsilon##?
2. How is ##\epsilon + a\cdot{p}=\epsilon## a gauge transformation? The gauge transformations I know are of the form ##A_{\mu}\rightarrow A_{\mu}+\partial_{\mu}\Lambda##.
Physical polarization vectors are unchanged under a gauge transformation ##\epsilon + a\cdot{p}=\epsilon##, where ##a## is some arbitrary constant.
1. Why are physical polarization vectors transverse?
2. Why is ##p\cdot{\epsilon}=0## the condition for the transverseness of ##\epsilon##?
2. How is ##\epsilon + a\cdot{p}=\epsilon## a gauge transformation? The gauge transformations I know are of the form ##A_{\mu}\rightarrow A_{\mu}+\partial_{\mu}\Lambda##.