# Ballistic Aggregation in Systems of Inelastic Particles: Cluster growth, structure and aging

## TL;DR

This paper investigates the dynamics of granular gases and aggregating clusters in one and two dimensions, revealing aging phenomena and confirming the applicability of ballistic aggregation mechanisms across these systems.

## Contribution

It provides detailed simulation results on structure, dynamics, and aging in granular gases and clusters, establishing their equivalence in one dimension.

## Key findings

- Ballistic aggregation applies in 1D granular gases.
- Aging phenomena exhibit scaling similar to phase transition kinetics.
- Structural properties are linked to autocorrelation function behavior.

## Abstract

We study far-from-equilibrium dynamics in models of freely cooling granular gas and ballistically aggregating compact clusters. For both the cases, from event driven molecular dynamics simulations we have presented detailed results on structure and dynamics in space dimensions $d=1$ and $2$. Via appropriate analyses it has been confirmed that the ballistic aggregation mechanism applies in $d=1$ granular gases as well. Aging phenomena for this mechanism, in both the dimensions, have been studied via the two-time density autocorrelation function. This quantity is demonstrated to exhibit scaling property similar to that in the standard phase transition kinetics. The corresponding functional forms have been quantified and discussed in connection with the structural properties. Our results on aging establish a more complete equivalence between the granular gas and the ballistic aggregation models in $d=1$.