Re: photon reflection


shevek wrote:
> Tom Roberts wrote:
> > solar plexus wrote:
> > > i wonder what happens when photons/ light is reflected
> > > from matterial surfaces
> > > are the photons first absorbed then emited, due to the
> > > higher energi state of the surface atoms or
> > > the same photons hitting the surface are reflected phase shifted
> >
> > As I so often do around here, I suggest you not attempt to discuss
> > photons until you have studied QED. Once you do that, you'll
realize
> > that your question simply does not make sense.
> >
> > Basically it is not possible to distinguish between
> > "incident" and "reflected" photons. You can collect
> > the Feynman diagrams in a way that could be described
> > as photons being absorbed and re-emitted, and you can
> > collect them in a way that could be described as a
> > single set of photons being phase-shifted by the
> > mirror....
> >
> > So in a sense BOTH of your guesses are correct. Welcome
> > to the weird and wonderful world of QED....
> >
> > The same dichotomy applies to light rays: For light rays, it is
clear
>
> > that reflection can be described in the geometric optics
> approximation
> > as a new ray being emitted, and in the wave optics approximation as
> an
> > interference effect applied to a single wave.
> >
> >
> > Note my statement about the indistinguishability of the photons
holds
>
> > even for the case of a moving mirror -- for light rays the
reflected
> ray
> > is of different frequency and wavelength than the incident ray, and
> yet
> > the photons cannot be distinguished (you can make measurements
using
> > directional detectors that can tell the difference between the
rays,
> but
> > you cannot identify where the photons came from, incident or
> reflection).
> >
> > Repeat the mantra: photons are _quantum_objects_ and
> > are not like anything of your everyday experience.
> >
> >
>
>
> Nicely put Tom, but I would make one change to your mantra:
>
> "photons are _quantum_objects_ and
> everything of your everyday experience is based on them".

xxein:

The universe: That which we rape in our own name.

.

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