Phase Transitions and Their Bifurcation Analysis in a Large Population of Active Rotators with Mean-Field Coupling

Bifurcation structures associated with the onset of macroscopic rhythms in a large population of active rotators are analyzed theoretically and numerically. The phase transition involving hysteresis found numerically in a previous work are investigated in greater detail with particular attention to codimension-two bifurcation points. As a result, unexpectedly rich bifurcation structures are revealed.