Traveling Waves in the McKean-Vlasov Equation under Sakaguchi-Kuramoto Interaction with Phase Frustration
Jesenko Vukadinovic
TL;DR
This work analyzes the McKean-Vlasov equation for weakly coupled oscillators under the Sakaguchi-Kuramoto interaction with phase frustration $α$. By reducing the one-mode coupling problem to a finite-dimensional system and introducing an asymmetrically extended von Mises distribution (AvMPDF), the authors derive a traveling-wave McKean-Vlasov equation whose coherence is captured by a pair $(r,k)$ of order-parameter and wave speed. The main result proves a continuous global phase transition at $μ_α = 2\sec α$, from incoherence to a unique traveling-wave coherent state for $α∈(0,π)$, with special cases: a coherent stationary state for $α=0$ (or $π$) when $μ>2$, and no traveling waves at $α=π/2$. The analysis hinges on an asymmetrical extension of the modified Bessel functions and a detailed monotonicity study, providing a rigorous framework for traveling waves in non-symmetric, phase-frustrated coupling. This advances mathematical understanding of synchronization with delays in neural-like networks and broadens the spectrum of phase transitions beyond symmetric Kuramoto-type interactions.
Abstract
We study the McKean-Vlasov equation for weakly coupled oscillators subject to the Sakaguchi-Kuramoto interaction. While the Kuramoto interaction provides a good approximation for small, densely connected networks, time delays in larger networks lead to symmetry-breaking phase offsets (frustrations). The Sakaguchi-Kuramoto interaction is the simplest such generalization, featuring a single frustration parameter. We establish the existence of a continuous global phase transition from incoherence to coherence, in the form of a propagating asymmetrically extended von Mises probability distribution function (AvMPDF). The corresponding traveling wave equation reduces to a system of two equations in two unknowns: the order parameter for the AvMPDF and the wave speed. The analysis relies on an appropriate asymmetrical extension of the modified Bessel function.
