Parabolic model with phase-jump coupling
  We study the coherent dynamics of a two-level parabolic model and ways to enhance population transfer and even to obtain complete population inversion in such models. Motivated by the complete population inversion effect of zero-area pulses found in [1], we consider a scheme where a given coupling function is transformed to a zero-area coupling by performing phase-jump in the middle of the evolution. We also derive a universal formula for the effect of the phase-jump. 
Jaakko Lehto and Kalle-Antti Suominen
quant-ph