Let us look closely at the effective equations of motion for the Fourier components of the electron density in the limit where plasma oscillations occur. We showed in the previous chapter that, in the limit , the Fourier components obey the equations of motion
i.e. those of a harmonic oscillator. However, harmonic excitations obey Bose statistics. This suggests that plasma oscillations in some way represent bosonic excitations of the interacting electron gas. Equivalently, plasma oscillations can be thought of as harmonic ...