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DanP
- 114
- 1
Im trying to make my way through Feynman's "QED: Strange theory of light and matter". On page 89 he says:
How should I understand this ? Is he referring strictly to the speed of light "C" not "c" in a specific medium , in a transparent medium ? I am kinda puzzled by amplitudes greater than c.
It may surprise you that there is an amplitude for a photon to go faster or slower than the conventional speed c. The amplitudes for those possibilities are very small compared to to the contribution from speed c;in fact they cancel out when light travels long distances.
How should I understand this ? Is he referring strictly to the speed of light "C" not "c" in a specific medium , in a transparent medium ? I am kinda puzzled by amplitudes greater than c.