Is diffusion anomalous in two-dimensional Yukawa liquids?

TL;DR

This study investigates diffusion behavior in two-dimensional Yukawa liquids, revealing that apparent anomalous diffusion depends on dissipation and measurement timing, but long-term behavior tends toward normal diffusion.

Contribution

It demonstrates that diffusion anomalies in Yukawa liquids are influenced by dissipation and measurement timing, clarifying previous conflicting predictions.

Findings

Anomalous diffusion depends on dissipation strength.

Subdiffusion can occur with high friction.

Long-term diffusion tends to be normal.

Abstract

There have recently been many predictions of "superdiffusion" in two-dimensional strongly coupled Yukawa systems, both by computer simulations and in dusty plasma experiments, with substantially varying diffusion exponents. Here we show that the results crucially depend on the strength of dissipation and the time instant of the measurement. For sufficiently large friction even subdiffusion is possible. However, there are strong indications that, in the long-time limit, anomalous diffusion vanishes for dissipative as well as for frictionless systems.