# Harmonically confined particles with long-range repulsive interactions

## TL;DR

This paper analyzes a classical particle system confined by a harmonic trap with long-range repulsive interactions, deriving exact density profiles for large N and revealing complex dependence on the interaction parameter k.

## Contribution

It provides an exact computation of the average density profile for a broad class of long-range interacting particles under harmonic confinement, generalizing known models.

## Key findings

- Density profile is independent of temperature at low temperatures.
- Distinct behaviors of the density profile for different ranges of k.
- Exact solutions for large N across all k > -2.

## Abstract

We study an interacting system of $N$ classical particles on a line at thermal equilibrium. The particles are confined by a harmonic trap and repelling each other via pairwise interaction potential that behaves as a power law $\propto \sum_{\substack{i\neq j}}^N|x_i-x_j|^{-k}$ (with $k>-2$) of their mutual distance. This is a generalization of the well known cases of the one component plasma ($k=-1$), Dyson's log-gas ($k\to 0^+$), and the Calogero-Moser model ($k=2$). Due to the competition between harmonic confinement and pairwise repulsion, the particles spread over a finite region of space for all $k>-2$. We compute exactly the average density profile for large $N$ for all $k>-2$ and show that while it is independent of temperature for sufficiently low temperature, it has a rich and nontrivial dependence on $k$ with distinct behavior for $-2<k<1$, $k>1$ and $k=1$.