E=hw. is this always true?

[I_wonder]

Has anyone ever come across any experiments suggesting that the E=hw law for the energy of photons may require some correction, especially in the case of low energy photons ?

 

[Andy Resnick]

E = hw is not a law, in the sense of thermodynamic laws or Newton's laws. E = hw is nothing more than a relationship between a massless particle's energy and the corresponding wave's angular frequency. There may be some research on time-dependencies of h, but I don't know of anything serious.