The Quantum state diffusion model and the driven damped nonlinear   oscillator
  We consider a driven damped anharmonic oscillator which classically leads to a bistable steady state and to hysteresis. The quantum counterpart for this system has an exact analytical solution in the steady state which does not display any bistability or hysteresis. We use quantum state diffusion theory to describe this system and to provide a new perspective on the lack of hysteresis in the quantum regime so as to study in detail the quantum to classical transition. The analysis is also relevant to measurements of a single periodically driven electron in a Penning trap where hysteresis has been observed. 
M. Rigo, G. Alber, F. Mota-Furtado, P. F. O'Mahony