Bifurcations and stability of synchronized solutions in the Kuramoto model with uniformly spaced natural frequencies

Abstract We consider the classical Kuramoto model (KM) with natural frequencies and its continuum limit (CL), and discuss the existence of synchronized solutions and their bifurcations and stability. We specifically assume that the frequency function is symmetric and linear in the CL, so that the natural frequencies are evenly spaced in the KM. We show that in the KM, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>O</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mn>2</mml:mn> <mml:mi>n</mml:mi> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> one-parameter families of synchronized solutions are born and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>O</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mn>2</mml:mn> <mml:mi>n</mml:mi> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> saddle-node and pitchfork bifurcations occur at least, when the node number n is odd and tends to infinity. Moreover, we prove that a family of synchronized solutions obtained in the previous work suffers a saddle-node bifurcation at which its stability changes from asymptotically stable to unstable and the other families of synchronized solutions are unstable in the KM. For the CL, we show that a one-parameter family of continuous synchronized solutions obtained in the previous work is asymptotically stable and that there exist uncountably many one-parameter families of discontinuous synchronized solutions and they are unstable along with another one-parameter family of continuous synchronized solutions.