Quantum mechanical representation of acoustic streaming and acoustic radiation pressure

Abstract

We discuss acoustic streaming and acoustic radiation pressure from the viewpoint of energy and momentum of acoustic waves, using a quantum mechanical representation of acoustic waves. We represent the energy ɛ and momentum μ of acoustic waves as $\varepsilon {=n}_pħ\omega$ and $\mu {=n}_pħk;$ here $n_p$ is the phonon density, ω is the frequency, k is the wave number, and ħ is Planck’s constant. It is easy to derive the momentum of acoustic waves as $\mu =\varepsilon /c$ $(c$ is the sound velocity). Therefore, we can represent the acoustic streaming and acoustic radiation pressure in terms of the momentum.