Do Forces Act on Photons?

  At first glance evidence appears to support the assumption that light receives an impulse on entering a denser medium but that implies photons are acted on by forces. The same could be said for reflection and Compton scattering since there is a change in the direction of of the photon's motion. Radiation pressure and emission recoil also suggest the photons experience momentum changes. Even x-rays whose wavelength is small compared to atomic spacing are slightly refracted.

An alternative explanation is a change in the nature of the medium. Maxwell's electromagnetic wave equation tells us that the speed of light depends on the permeability and permittivity of the medium but how does that explain the change in the direction of the photons? Huygens' principle explains the change in the direction of the wavefront of a single plane wave as due to the phase difference along the boundary of the medium and reduced speed in the denser medium. 

Another explanation of refraction is the induction of secondary waves in the medium. 

We use logical implication to reject premises whose conclusions do not agree with observation. One concludes that if the results are false the premises must also be false since truth is not deceiving. The problem is that false premises and arguments can yield truthful conclusions. So we are left in a quandary. 

We can look for more facts concerning refraction such as the Fresnel equations for the transmission and reflection of light at boundary between two media but the coefficients are consistent with the deductions so we have nothing contrary to the premises. 

Fresnel, Mémoire sur la Loi des modifications de la réflexion imprime á la lumière polarisée

What might be the nature of a boundary force capable of deflecting light? The General Theory of Relativity tells us that the path of light is affected by gravitational fields. Matter also has cohesive forces that hold its particles together. It is surrounded by a potential field that extends beyond its boundaries that exert forces on nearby particles. Can we rule out such a cohesive force also acting on light?