Socioeconomic agents as active matter in nonequilibrium Sakoda-Schelling models

TL;DR

This paper investigates the robustness of socioeconomic agent-based models, especially the Sakoda-Schelling model, revealing their nonequilibrium dynamics, phase separation phenomena, and connections to active matter physics, including non-reciprocal interactions.

Contribution

It introduces a unifying field-theoretic framework for analyzing socioeconomic models, linking agent decision rules to active matter dynamics and exploring non-reciprocal population interactions.

Findings

Model exhibits nonequilibrium behavior with equilibrium-like phase separation.

Mapping to active matter field description provides new analytical insights.

Non-reciprocal interactions induce non-steady macroscopic dynamics.

Abstract

How robust are socioeconomic agent-based models with respect to the details of the agents' decision rule? We tackle this question by considering an occupation model in the spirit of the Sakoda-Schelling model, historically introduced to shed light on segregation dynamics among human groups. For a large class of utility functions and decision rules, we pinpoint the nonequilibrium nature of the agent dynamics, while recovering the equilibrium-like phase separation phenomenology. Within the mean field approximation we show how the model can be mapped, to some extent, onto an active matter field description. Finally, we consider non-reciprocal interactions between two populations, and show how they can lead to non-steady macroscopic behavior. We believe our approach provides a unifying framework to further study geography-dependent agent-based models, notably paving the way for joint consideration of population and price dynamics within a field theoretic approach.