The hysteresis cycle in the gradient picture.

<p>The diagrams show the stages of one hysteresis cycle starting from (<b>A</b>) with the state at as represented by the sphere. Decreasing creates the asymmetric situation (<b>B</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 (<b>C</b>). Increasing until brings us back to the initial situation with the state shifted to the other well see (<b>D,E</b>). The diagrams (<b>F</b>) and (<b>G</b>) depict the switching from the minimum at to the minimum at by increasing . By decreasing until the hysteresis cycle is finished, see (<b>H,I</b>).