The study of amplitude and phase relaxation impact on the quality of   quantum information technologies
  The influence of amplitude and phase relaxation on evolution of quantum states within the formalism of quantum operations is considered. The model of polarizing qubits where noises are determined by the existence of spectral degree of freedom that shows up during the light propagation inside anisotropic mediums with dispersion is studied. Approximate analytic model for calculation of phase plate impact on polarizing state with dispersion influence taken into consideration is suggested. 
Yu.I. Bogdanov, B.I. Bantysh, A.Yu. Chernyavskiy, V.F. Lukichev, A.A.   Orlikovsky
quant-ph