Quantum Dynamics of a Microwave Driven Superconducting Phase Qubit Coupled to a Two-Level System

TL;DR

This paper provides an analytical model and experimental validation of the complex quantum dynamics in a microwave-driven superconducting phase qubit coupled to a two-level system, revealing novel phenomena like anomalous Rabi oscillations and two-photon transitions.

Contribution

It offers a comprehensive theoretical description and experimental verification of quantum phenomena in a driven qubit-TLS system across various microwave field strengths.

Findings

Observation of anomalous Rabi oscillations

Detection of high-contrast beatings in Rabi oscillations

Experimental confirmation of two-photon transitions

Abstract

We present an analytical and comprehensive description of the quantum dynamics of a microwave resonantly driven superconducting phase qubit coupled to a microscopic two-level system (TLS), covering a wide range of the external microwave field strength. Our model predicts several interesting phenomena in such an ac driven four-level bipartite system including anomalous Rabi oscillations, high-contrast beatings of Rabi oscillations, and extraordinary two-photon transitions. Our experimental results in a coupled qubit-TLS system agree quantitatively very well with the predictions of the theoretical model.