Cavity quantum electrodynamics with dressed states of a superconducting artificial atom

TL;DR

This paper experimentally investigates the microwave response of a transmon artificial atom coupled to two resonant modes, revealing dressed states and multi-photon processes, advancing understanding of cavity QED with superconducting qubits.

Contribution

It demonstrates a novel method to study dressed states and multi-photon processes in a superconducting artificial atom system using coupled resonant modes.

Findings

Observation of dressed states with multiple excited levels

Modulation of probe transmission by microwave amplitude

Identification of multi-photon inter-level transitions

Abstract

We experimentally studied the microwave response of a transmon artificial atom coupled to two closely spaced resonant modes. When the atom is under driven with one of the modes, the atom state and mode photons are superposed, forming the dressed states. Dressed states with 1st, 2nd and 3rd excited states of the atom were prepared and probed via the strong coupling to the other resonant mode from the point of view of cavity quantum electrodynamics. The transmission of the probe tone is modulated by the driving microwave amplitude, displaying multi-photon process associated with the inter-atomic level transitions. Our system provides an easy method to study the dressed states by driving one mode and probing the Landau-Zener transition of the other.