Secular versus nonsecular Redfield dynamics and Fano coherences in incoherent excitation: An experimental proposal

Two different master-equation approaches are formally derived to address the dynamics of open quantum systems interacting with a thermal environment (such as sunlight). They lead to two physical results: nonsecular equations, which show noise-induced (Fano) coherences; and secular equations, which do not. An experimental test for the appearance of nonsecular terms is proposed using Ca atoms in magnetic fields excited with broadband incoherent radiation. Significantly different patterns of fluorescence are predicted, allowing for a clear test of the validity of the secular and nonsecular approach and for the observation of Fano coherences.