Density of states of colloidal glasses

TL;DR

This paper investigates the vibrational modes of colloidal glasses using solid state physics concepts, revealing unique low-frequency modes that differ from typical solid vibrations and extend over large scales.

Contribution

It introduces an experimental approach to analyze colloidal glasses' vibrational modes from a solid state physics perspective, highlighting novel low-frequency modes.

Findings

Identification of soft low-frequency vibrational modes

Modes extend over large length scales

Distinct from acoustic vibrations in ordinary solids

Abstract

Glasses are structurally liquid-like, but mechanically solid-like. Most attempts to understand glasses start from liquid state theory. Here we take the opposite point of view, and use concepts from solid state physics. We determine the vibrational modes of a colloidal glass experimentally, and find soft low-frequency modes that are very different in nature from the usual acoustic vibrations of ordinary solids. These modes extend over surprisingly large length scales.