My question is about phase and group velocities in a monoatomic crystal. I want to find the speed of sound, so I am using the equation for vibrational modes: ...
I want to simply calculate the phase velocity of a mode in a dielectric loaded waveguide but am having difficulty arriving at a sensible answer. Here I consider only a TM mode. The problem is ...
If I have to show that the group velocity of a free particle is twice the phase velocity, is the following argument correct (avoiding to use the wave function and the momentum operator): For a ...