The Stimulated Raman Adiabatic Passage on a three-state system interacting with a spin bath is considered focusing on the efficiency of the population transfer. Our analysis is based on the perturbation treatment of the interaction term evaluated beyond the Rotating Wave Approximation, thus focusing on the limit of weak system-bath coupling. The analytical expression of the correction to the efficiency and consequent numerical analysis show that in most of the cases the effects of the environment are negligible, confirming the robustness of the population transfer.
Comment: 11 pages, 3 figures