One-dimensional inelastic collapse of four particles: asymmetric collision sequences and spherical billiard reduction

TL;DR

This paper investigates the inelastic collapse of four particles in a one-dimensional system, analyzing asymmetric collision sequences, their realizability, and reducing the system to a lower-dimensional dynamical system to study collision order patterns.

Contribution

It introduces a novel reduction of the four-particle system to a smaller dynamical system and analyzes asymmetric collision sequences, including their stability and numerical behavior.

Findings

Asymmetric collision patterns can be realized despite instability.

The four-particle system can be reduced to a lower-dimensional dynamical system.

Numerical simulations suggest the system's orbits may be quasi-periodic.

Abstract

We consider a one-dimensional system of four inelastic hard spheres, colliding with a fixed restitution coefficient $r$, and we study the inelastic collapse phenomenon for such a particle system. We study a periodic, asymmetric collision pattern, proving that it can be realized, despite its instability. We prove that we can associate to the four-particle dynamical system another dynamical system of smaller dimension, acting on $\{1,2,3\} \times \mathbb{S}^2$, and that encodes the collision orders of each trajectory. We provide different representations of this new dynamical system, and study numerically its $\omega$-limit sets. In particular, the numerical simulations suggest that the orbits of such a system might be quasi-periodic.