Learning About Phonons with Frequencies Below One kHz

Abstract

Two areas of interest in phonon research are effects in highly disordered solids and nonlinear effects. When phonons propagate in a disordered potential field, they may become Anderson localized, in a fashion similar to electron Schrodinger waves in disordered metals. If there are nonlinear interactions, the question arises as to whether or not the nonlinearity will weaken the Anderson localization. Recently we have been studying such questions using macroscopic acoustic analogs of linear and nonlinear wave propagation in disordered, as well as ordered systems. These systems, designed to precisely simulate certain problems in phonon and electron physics, are operated at frequencies below 1 KHz. We have also used such a system to study the vibrational properties of a 2-D quasicrystal.