Phases and correlations in active nematic granular systems

TL;DR

This paper uses numerical simulations to study phase transitions, ordering, and dynamics in vibrated active granular rods, revealing long-range order, periodic phases, and diffusion behaviors.

Contribution

It provides new insights into phase behavior and dynamics of vibrated granular rods, including the discovery of a periodic ordering phase and detailed diffusion analysis.

Findings

Confirmation of long-range nematic order in the system

Identification of a periodic ordering phase disrupting translation symmetry

Translational diffusivity increases with rod concentration

Abstract

We investigate the statistical behavior of a system comprising fore-aft symmetric rods confined between two vertically vibrating plates using numerical simulations closely resembling the experimental setup studied by Narayan et al., Science 317, 105 (2007). Our focus lies in studying the phase transition of the system from an isotropic phase to a nematic phase as we increase either the rod length or the rod concentration. Our simulations confirm the presence of long-range ordering in the ordered phase. Furthermore, we identify a phase characterized by a periodic ordering profile that disrupts translation symmetry. We also provide a detailed analysis of the translational and rotational diffusive dynamics of the rods. Interestingly, the translational diffusivity of the rods is found to increase with the rod concentration.