Autler-Townes splitting vs. electromagnetically induced transparency: objective criterion to discern between them in any experiment

Autler-Townes splitting (ATS) and electromagnetically-induced transparency (EIT) both yield a transparency window in an absorption profile, but only EIT yields strong transparency for a weak pump field, due to Fano interference, whereas ATS does not. Fano interference thus makes EIT especially valuable for sensing, so discriminating EIT from ATS is important but so far has been subjective. We introduce an objective method, based on Akaike's information criterion, to test ATS vs. EIT from experimental data and determine which pertains. We apply our method to a recently reported induced-transparency experiment in superconducting circuit quantum electrodynamics.