sci.physics.electromag

Darwin123 wrote:
> Why would
> you need perturbation theory if virtual photons had a precisely
> determined energy?

Do not confuse a basis of modes [1] with the state described
using these modes.

[1] Each of which may well have a precisely determined energy.

--
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Dr. Paul Kinsler
Blackett Laboratory (QOLS) (ph) +44-20-759-47520 (fax) 47714
Imperial College London, Dr.Paul.Kinsler@physics.org
SW7 2BW, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/