What makes a complex liquid complex?

TL;DR

This paper models a complex liquid as a network of particle bonds, revealing hierarchical structures and dynamic phenomena that are crucial for understanding the behavior of complex fluids and glasses.

Contribution

It introduces a network-based framework to analyze the dynamics of complex liquids, highlighting hierarchical structures and critical behaviors.

Findings

Stretched-exponential decay of network memory

Power-law distribution of particle neighbor retention times

Evidence of a possible dynamical critical point

Abstract

We view a complex liquid as a network of bonds connecting each particle to its nearest neighbors; the dynamics of this network is a chain of discrete events signaling particles rearrangements. Within this picture, we studied a two-dimensional complex liquid and found a stretched-exponential decay of the network memory and a power-law for the distribution of the times for which a particle keeps its nearest neighbors; the dependence of this distribution on temperature suggests a possible dynamical critical point. We identified and quantified the underlying spatio-temporal phenomena. The equilibrium liquid represents a hierarchical structure, a mosaic of long-living crystallites partially separated by less-ordered regions. The long-time dynamics of this structure is dominated by particles redistribution between dynamically and structurally different regions. We argue that these are generic features of locally ordered but globally disordered complex systems. In particular, these features must be taken into account by any coarse-grained theory of dynamics of complex fluids and glasses.