Chimera states (Kuramoto & Battogtokh 2002, named by Abrams & Strogatz 2004) occur in rings of
non-locally coupled identical phase oscillators with coupling G(x) = (1/2π)cos(x − α).
Spontaneously, some oscillators synchronize while others remain incoherent — a counterintuitive
coexistence in a symmetric, identical system.