Mixed phases in feedback Ising models

We study mean-field Ising models in which the coupling depends on the magnetization via a feedback function.

We identify mixed phases (MPs) and show that they can be stable at zero temperature for sufficiently strong feedback.

Moreover, stable MPs are always super-stable, meaning that perturbations decay linearly in time.

Feedback Ising models (FIMs) provide a useful framework for phase transformations between aligned phases via stable and unstable intermediate phases in multistable systems.

We also analyze the dynamical behavior of FIMs driven by a varying magnetic field and discuss basic properties of finite-dimensional FIMs.