I asked if the rest mass of a photon is still zero in non-vacuum, where it's velocity is less than c. I got the answer that it is indeed still zero, because the length of the 4-vector (E/c,px,py,pz) is zero. And because this is a flat space property it's easily generalised to other coupled fields to describe non-vacuum situations: the result still holds. Now my problem is that I don't know what a flat-space property is, i.o.w. why the four-vector is still zero.
2006-08-15
04:54:50
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4 answers
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asked by
helene_thygesen
4