Originally Posted By: Bill 6
The operative term being 'no known way'.

True, but if there isn't a known way then you will have to come up with a way that wasn't previously known, and then you will have to provide a solid theoretical basis for your new way.
Originally Posted By: Bill 6
... the atoms in a glass block will, according to quantum theory, absorb the original photon then emit their own photon.

There is a Wikipedia article about refractive index that explains the lower speed of light through a medium. The photons are not absorbed and re-emitted by the atoms of the medium. Instead they interact with the atoms to drag them off a little and then let them go back where they were. This produces a drag on the photon motion that slows the photon down.

Bill

C is not the speed of light in a vacuum.
C is the universal speed limit.