Anomalous Damping of Sound in Smectic-ALiquid Crystals: Breakdown of Conventional Hydrodynamics?

Abstract
The attenuation of longitudinal ultrasound in smectic-A liquid crystals departs markedly from the quadratic frequency dependence predicted by hydrodynamics. The experimental results are compared to recent theoretical predictions of the breakdown of conventional hydrodynamics in smectic-A liquid crystals and other "one-dimensional crystals."