S. Kim et al., NONEQUILIBRIUM PHENOMENA IN GLOBALLY COUPLED ACTIVE ROTATORS WITH MULTIPLICATIVE AND ADDITIVE NOISES, ETRI journal, 18(3), 1996, pp. 147-160
We investigate noise-induced phase transitions in globally coupled act
ive rotators with multiplicative and additive noises. In the system th
ere are four phases, stationary one-cluster, stationary two-cluster, m
oving one-cluster, and moving two-cluster phases. It is shown that mul
tiplicative noise induces a bifurcation from one-cluster phase to two-
cluster phase. Pinning force also induces a bifurcation from moving ph
ase to stationary phase suppressing the multiplicative noise effect. A
dditive noise reduces both effects of multiplicative noise and pinning
force urging the system to the stationary one-cluster phase. The frus
trated effects of pinning force and additive and multiplicative noises
lead to a reentrant transition at intermediate additive noise intensi
ty. Nature of the transition is also discussed.