Figure 2. The hysteresis cycle in the gradient picture.

The diagrams show the stages of one hysteresis cycle starting from (A) with the state at as represented by the sphere. Decreasing creates the asymmetric situation (B). If the saddle-node bifurcation happens, i. e. both the maximum at z = 0 and the right minimum disappear so that the system shifts to the left minimum of the potential (C). Increasing until brings us back to the initial situation with the state shifted to the other well see (D,E). The diagrams (F) and (G) depict the switching from the minimum at to the minimum at by increasing . By decreasing until the hysteresis cycle is finished, see (H,I).