Forced one-dimensional swarmalator model

We study a simple model of swarmalators subject to periodic forcing and confined to moving around a one-dimensional ring. This is a toy model for physical systems with a mix of sync, swarming, and forcing, such as colloidal micromotors. We find rich behavior: pinned states where the swarmalators are locked to the driving, sync states where their phases are either identical or have fixed differences, and unsteady states, such as swarmalator chimera where the population splits into two sync dots enclosed by a "train" of swarmalators that run around a peanut-shaped loop. We derive the stability thresholds for most of these states which give us a good approximation of the model's phase diagram.