Tunable glassy dynamics in models of dense cellular tissue

TL;DR

This study investigates the tunable glassy dynamics in a 2D Voronoi model of dense cellular tissue, revealing regimes with standard and anomalous behaviors, and offers insights into designing materials with specific glassy properties.

Contribution

It demonstrates how varying the shape index in the Voronoi model can switch between typical and anomalous glassy behaviors, advancing understanding of tissue-like materials.

Findings

System properties can be tuned between standard and anomalous glassy regimes.

Viscosity may not diverge even as relaxation time increases.

Dynamical heterogeneities are strongly suppressed in the anomalous regime.

Abstract

Observations of glassy dynamics in experiments on confluent cellular tissue have inspired a wealth of computational and theoretical research to model their emergent collective behavior. Initial studies of the physical properties of several geometric cell models, including vertex-type models, have highlighted anomalous sub-Arrhenius, or "ultra-strong," scaling of the dynamics with temperature. Here we show that the dynamics and material properties of the 2d Voronoi model deviate even further from the standard glassforming paradigm. By varying the characteristic shape index $p_0$, we demonstrate that the system properties can be tuned between displaying expected glassforming behavior, including the breakdown of the Stokes-Einstein-Sutherland relation and the formation of dynamical heterogeneities, and an unusual regime in which the viscosity does not diverge as the characteristic relaxation time increase and dynamical heterogeneities are strongly suppressed. Our results provide further insight into the fundamental properties of this class of anomalous glassy materials, and provide a step towards designing materials with predetermined glassy dynamics.