When a three-level quantum system is irradiated by an intense coupling field resonant with two of the three possible transitions, the resonant absorption of the system from its ground state by an additional radiation field is suppressed. This effect, where the population is trapped in the ground state, is known in quantum optics as electromagnetically induced transparency . When the coupling field is detuned from resonance, the resonant absorption peak splits to form an Autler-Townes doublet . We observe these phenomena in a superconducting Josephson phase qubit, which can be considered an artificial atom with a multilevel quantum structure. These observations are qualitatively described by a simple model restricted to three energy levels. A full solution of the master equation including higher levels provides excellent agreement with all the experimental data.
Citation: Physical Review Letters
Pub Type: Journals
superconducting, Josephson qubit, Autler-Townes, EIT