|MadSci Network: Physics|
Hi Vamsi, Classical electrodynamics is the most successful theory in physics and for testing quantum electrodynamics predictions people always take classical limits. After the emergence of quantum mechanics and it was established that quantum mechanical description is the correct way of explaining all physical processes. After that one by one people started giving quantum mechanical treatment to all phenomenon. Well, in the time of Bohr and Sommerfield classical electrodynamics was the only established theory they tried to treat electron motion in atoms using classical electrodynamics and what so ever difficulties they were facing they were handling using assumptions. Now quantum electrodynamics is an approach to provide quantum mechanical treatment to electrodynamics. As such no special assumption has been made in quantum electrodynamics. Only you can say it takes quantum mechanics postulates. Here I am not saying that quantum electrodynamics as such has no new phenomenon and results of course there are many. For example various quantum states (nonclassical states) of field even the most basic spontaneous emission phenomena which can not be explained with out quantum elctrodynamics.
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