Autler-Townes effect in a superconducting three-level system

TL;DR

This paper demonstrates the Autler-Townes effect in a superconducting Josephson phase qubit, showing how intense coupling fields split absorption peaks, with experimental results matching theoretical models including dissipation and higher levels.

Contribution

First observation of the Autler-Townes effect in a superconducting qubit, validated by comprehensive modeling including dissipation and higher energy levels.

Findings

Spectroscopy peaks split under strong coupling fields

Experimental data agree with simple and complex theoretical models

Autler-Townes effect observed in superconducting artificial atoms

Abstract

When a three-level quantum system is irradiated by an intense coupling field resonant with one of the three possible transitions, the absorption peak of an additional probe field involving the remaining level is split. This process is known in quantum optics as the Autler-Townes effect. We observe these phenomena in a superconducting Josephson phase qubit, which can be considered an "artificial atom" with a multilevel quantum structure. The spectroscopy peaks can be explained reasonably well by a simple three-level Hamiltonian model. Simulation of a more complete model (including dissipation, higher levels, and cross-coupling) provides excellent agreement with all the experimental data.