Wiktionary
quantum acoustics
n. (context physics English) the study of the effects of the laws of quantum mechanics on the propagation and absorption of sound
Wikipedia
Quantum acoustics
In physics, quantum acoustics is the study of sound under conditions such that quantum mechanical effects are germane. For most applications, classical mechanics are sufficient to accurately describe the physics of sound. However very high frequency sounds, or sounds made at very low temperatures may be subject to quantum effects.
A symposium on quantum acoustics is held in Poland each year 1