Electromagnetic theory of sound and phonons in liquid
  Sound waves in and dielectric liquid, that consists of subsystems of valency electrons with effective mass and ions which interact through the long-wave potential electric field are considered, on analogies with and metallic liquid, but with the requirement, that electric current is absent. It is shown that usual description of sound wave in an ideal liquid as wave of mass density and mass velocity follows from the offered consideration. It is also shown that sound waves with other side can be considered as waves of potential electric field in an environment. Introduction of phonons in both cases is considered. 
A.A. Stupka
cond-mat.soft physics.plasm-ph quant-ph