Dynamical and structural properties of an absorbing phase transition: a case study from granular systems

TL;DR

This study explores the dynamical and structural aspects of absorbing phase transitions in granular systems, revealing both continuous and discontinuous transitions and developing theoretical models to explain these phenomena.

Contribution

It introduces a comprehensive analysis of APTs in granular systems, combining numerical simulations with kinetic and hydrodynamic theories to explain transition behaviors.

Findings

Both continuous and discontinuous transitions observed

Structural properties like hyperuniformity characterized

Theoretical models explain the role of synchronization in transitions

Abstract

We investigate the dynamical and structural properties of absorbing phase transitions (APTs) within granular systems. Specifically, we examine a model for vibrofluidized systems of spherical grains, which undergo a transition from a state of purely vertical motion to one characterized by horizontal diffusion as the density increases. Numerical simulations reveal that, depending on the specific system parameters, both continuous and discontinuous transitions can occur, each associated with markedly distinct structural properties at the transition point. We explain this using a theoretical analysis based on kinetic theory applied to an effective 2D model, which elucidates the role of a synchronization effect in determining the nature of the transition. A fluctuating hydrodynamic theory, which quantitatively describes the structural and dynamical properties of the active state such as hyperuniformity is derived from the microscopic dynamics, together with an equilibrium-like assumption concerning the noises on the hydrodynamic fields. This work expands on previous studies by providing a comprehensive examination of the APT characteristics and proposing new theoretical models to interpret the observed behaviors.