Quantum dynamics of a nanomagnet in a rotating field
  Quantum dynamics of a two-state spin system in a rotating magnetic field has been studied. Analytical and numerical results for the transition probability have been obtained along the lines of the Landau-Zener-Stueckelberg theory. The effect of various kinds of noise on the evolution of the system has been analyzed. 
C. Calero, E. M. Chudnovsky, and D. A. Garanin