Multistate transitions and quantum oscillations of optical activity
  We consider the effects of multistate transitions on the tunneling racemization of chiral molecules. This requires going beyond simple two-state models of enantiomers and to include transitions within a multiple-level quantum-mechanical system.We derive an effective two-level description which accounts for transitions from the enantiomers to an arbitrary number of excited states as an application of the Weisskopf-Wigner approximation scheme. Modifications to the optical activity from these additional states are considered in general terms under the assumption of \textit{CPT} invariance and then under T invariance. Some formal dynamical analogies between enantiomers and the neutral K-meson system are discussed. 
Celia Blanco and David Hochberg
quant-ph physics.optics