Non-Hermitian wave packet approximation for coupled two-level systems in   weak and intense fields
  We introduce an accurate non-Hermitian Schr\"odinger-type approximation of Bloch optical equations for two-level systems. This approximation provides a complete description of the excitation, relaxation and decoherence dynamics in both weak and strong laser fields. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically-adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters. 
Raiju Puthumpally-Joseph, Maxim Sukharev, Eric Charron
quant-ph physics.comp-ph physics.optics