Equilibria for an aggregation model with two species

TL;DR

This paper analyzes an aggregation model with two interacting species, classifies steady states, and studies their stability and existence regions using analytical and numerical methods, including a two-scale expansion for weak interactions.

Contribution

It provides a comprehensive classification of steady states and their stability in a two-species aggregation model, combining variational, linear stability, and numerical analyses.

Findings

Identified regions of existence and stability for steady states

Developed a two-scale expansion for weak cross-interactions

Performed numerical investigations for analytically intractable states

Abstract

We consider an aggregation model for two interacting species. The coupling between the species is via their velocities, that incorporate self- and cross-interactions. Our main interest is categorizing the possible steady states of the considered model. Notably, we identify their regions of existence and stability in the parameter space. For assessing the stability we use a combination of variational tools (based on the gradient flow formulation of the model and the associated energy), and linear stability analysis (perturbing the boundaries of the species' supports). We rely on numerical investigations for those steady states that are not analytically tractable. Finally we perform a two-scale expansion to characterize the steady state in the limit of asymptotically weak cross-interactions.