Stochastic Resonance and Nonlinear Response by NMR Spectroscopy
  We revisit the phenomenon of quantum stochastic resonance in the regime of validity of the Bloch equations. We find that a stochastic resonance behavior in the steady-state response of the system is present whenever the noise-induced relaxation dynamics can be characterized via a single relaxation time scale. The picture is validated by a simple nuclear magnetic resonance experiment in water. 
L. Viola, E. M. Fortunato, S. Lloyd, C.-H. Tseng, and D. G. Cory