Figure 1.

An illustration of a metabasin metadynamics hill function (top, eq 4) on the unit circle near the domain boundary (black lines denote r = 1) and its decomposition into a rescaled hill (left, eq 7) and a low plateau outside of the domain (right, eq 9). The hill is based on a Gaussian of width 1/√10 placed at r = 0.9. The effects of adding rescaled hill and exterior plateau contributions evenly over all points on the unit circle are exact complements, leading to bias updates that are flat everywhere when sampling is flat on the unit circle.