Velocity nonzero photon mass

In 1992, Vigier [46] surveyed the experimental status of nonzero photon mass. In 1940, de Broglie [46] arrived at an upper limit for the photon mass by estimating the experimental mesaurements of the dispersion of photons and comparing this dispersion with that predicted for a photon with finite mass. Photons with finite rest mass do not all travel at the same velocity, but one, dependent on the ratio of kinetic to rest mass energy. 

Starting from the equation with nonzero photon mass my, one gets dispersion relation k2 = co2c2 — p2. The group and phase velocities can be found to be... 

The effects of the nonzero electric conductivity were further investigated by Roy et al. [20,50-52]. They have shown that the introduction of a nonzero conductivity yields a dispersion relation that results in phase and group velocities depending on a corresponding nonzero photon rest mass, due to a tired-light effect. 

In all approaches with a nonzero photon rest mass the velocity c should be considered as an asymptotic limit at infinite energy that can never be fully approached in physical reality by a single photon in vacuo. 

This is unphysical. But if we take the phase velocity in de Broglie relation, we get a physical solution, namely, the real nonzero rest mass of photon. Since the mid 1990s, there has been much interest in the vg / c solutions of Maxwell equations [40]. However, in our framework, taking the phase velocity in de Broglie relation (59), we get... 

Evidently light has wave and particle aspects, and we can describe it in terms of photons, which are associated with waves of frequency v = E/h. Now photons are rather peculiar particles in that they have zero rest mass. In fact, they can exist only when traveling at the speed of light. The more normal particles in our experience have nonzero rest masses and can exist at any velocity up to the speed-of-light limit. Are there also waves associated with such normal particles ... 

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