Viscoelasticity of 2D liquids quantified in a dusty plasma experiment

TL;DR

This study measures the viscoelastic properties of 2D liquids in a dusty plasma experiment, introducing a method to quantify wavenumber-dependent viscosity and revealing elastic behavior through particle tracking.

Contribution

It presents a novel experimental approach to measure wavenumber-dependent viscosity in 2D liquids, including friction effects, and validates findings with simulations.

Findings

Wavenumber-dependent viscosity $\\eta(k)$ measured experimentally.

Oscillations in TCAF indicate elastic contributions.

Experimental results align with Yukawa liquid simulations.

Abstract

The viscoelasticity of two-dimensional liquids is quantified in an experiment using a dusty plasma. An experimental method is demonstrated for measuring the wavenumber-dependent viscosity, $\eta(k)$, which is a quantitative indicator of viscoelasticity. Using an expression generalized here to include friction, $\eta(k)$ is computed from the transverse current autocorrelation function (TCAF), which is found by tracking random particle motion. The TCAF exhibits an oscillation that is a signature of elastic contributions to viscoelasticity. Simulations of a Yukawa liquid are consistent with the experiment.