Construction of exact solutions of Bloch-Maxwell equation based on   Darboux transformation
  A new strategy, using Darboux transformations, of finding self-switching solutions of $i\dot{\rho} = [H, f({\rho})]$ is introduced. Unlike the previous ones, working for any f but for Hamiltonians whose spectrum contains at least three equally spaced eigenvalues, the strategy does not impose any restriction on the discrete part of the spectrum of H. The strategy is applied to the Bloch-Maxwell system. 
Maciej Kuna