Hi, I've been doing Quantum Electrodynamics,and I've just finished the third chapter of QED-the strange theory of light and matter,by Richard Feynman. I have just three questions in regard to this... 1. what does Feynman mean when he says that any electron or photon can be polarized relative to the dimensions of space and time, and so there are 4 possible states of polarization- X,Y,Z,T....(I'm specially confused as to what the T here is..if it's time,how can an electron be polarised in the time direction?) Also,he says that electrons can exist in 4 conditions of polarization...but since polarization is basically the spin of an electron...and an electron can only have a spin of +/- 1/2 (only 2 possibilities),...this doesn't make sense. (pg 120, QED-the strange theory of light and matter) 2. What does Feynman mean by the magnetic moment of an electron....he calculates it by adding up the probabilities of all the ways a photon from a magnetic field can interact with an electron....how can interpret this? ( Third chapter, QED-the strange theory of light and matter) 3. Unlike electrons,(which may change their polarization states while travelling from one point to another in space-time),why are photons not able to change their polarisation states after being emitted from their sources?