NOISE-INDUCED PHASE-TRANSITION IN SOFT ISING SPINS WITH A FLUCTUATINGINTERACTION

We investigate noise-induced phase transitions in soft Ising spins, wh ich have continuous values, with a fluctuating interaction within the framework of the mean-field scheme. The fluctuating interaction provid es an effective ferromagnetic coupling, leading to a ferromagnetic ord er. The interplay of the fluctuating interaction and an additive noise leads to a reentrant transition, triple transitions, and a softening of the order parameter, presenting a weak order in the ordered phase. In the limit of Ising spins the fluctuating interaction renormalizes t he mean field, reducing the critical intensity of the additive noise.