Packing of softly repulsive particles in a spherical box - a generalised Thomson problem

TL;DR

This paper investigates the equilibrium configurations of softly repulsive particles confined in a spherical space, analyzing how different interaction potentials influence their shell structures and comparing numerical results with continuum models.

Contribution

It introduces a generalized Thomson problem for particles with inverse power law interactions and provides extensive numerical simulations up to 5000 particles across different regimes.

Findings

Numerical results align better with continuum models as particle number increases.

Different interaction exponents lead to distinct shell structures.

The study extends the classical Thomson problem to softer repulsive interactions.

Abstract

We study the (near or close to) ground state distribution of N softly repelling particles trapped in the interior of a spherical box. The charges mutually interact via an inverse power law potential of the form $1/r^\gamma$. We study three regimes in which the charges form an single spherical shell at the edge of the box ($\gamma=1$), a series of concentric shells of increasing density ($\gamma=2$) and $\gamma=12$ for which the charges form shells with a more uniform charge distribution. We conduct numerical simulations for clusters containing up to 5000 charges and compare charge density across the system with continuum limit results. The agreement between numerical (discrete) results and the continuum limit is found to improve with increasing N.