Abstract

We investigate electromagnetically induced transparency and Autler–Townes splitting in a superconducting quantum circuit with a four-level V-type energy spectrum constructed by two coupled superconducting charge qubits. We show that it is possible for this four-level superconducting system to exhibit multiple dips in the absorption spectrum of a probe field, with at most three dips resulting from a combination of two ATS subsystems, which indicates the breakdown of the traditional correspondence between a \\) -level system and \ dips. It is also shown that the switching from EIT to ATS can be realized in a three-level ladder-type subsystem