First-order phase transitions in the Kuramoto model with compact bimodal frequency distributions

TL;DR

This paper analyzes how first-order phase transitions and hysteresis occur in the Kuramoto model with compact bimodal frequency distributions, revealing the route to synchronization involves a standing wave regime.

Contribution

It provides a rigorous bifurcation analysis of the Kuramoto model with compact bimodal distributions using an innovative combination of analytical methods.

Findings

Route to synchronization involves standing wave regime

Bifurcation diagram for order parameter dynamics derived

Transitions differ based on support of unimodal distributions

Abstract

The Kuramoto model of a network of coupled phase oscillators exhibits a first-order phase transition when the distribution of natural frequencies has a finite flat region at its maximum. First-order phase transitions including hysteresis and bistability are also present if the frequency distribution of a single network is bimodal. In this study we are interested in the interplay of these two configurations and analyze the Kuramoto model with compact bimodal frequency distributions in the continuum limit. As of yet, a rigorous analytic treatment has been elusive. By combining Kuramoto's self-consistency approach, Crawford's symmetry considerations, and exploiting the Ott-Antonsen ansatz applied to a family of rational distribution functions that converge towards the compact distribution, we derive a full bifurcation diagram for the system's order parameter dynamics. We show that the route to synchronization always passes through a standing wave regime when the bimodal distribution is compounded by two unimodal distributions with compact support. This is in contrast to a possible transition across a region of bistability when the two compounding unimodal distributions have infinite support.