Continuous Monitoring of Rabi Oscillations in a Josephson Flux Qubit

TL;DR

This paper demonstrates continuous observation of Rabi oscillations in a Josephson flux qubit using a tank circuit, achieving a long coherence time of 2.5 microseconds and a high quality factor, advancing qubit measurement techniques.

Contribution

It introduces a continuous Rabi spectroscopy method for flux qubits, enabling longer coherence times and improved measurement fidelity.

Findings

Achieved a coherence time of about 2.5 microseconds.

Demonstrated continuous monitoring of Rabi oscillations.

Measured an effective qubit quality factor of approximately 7000.

Abstract

Under resonant irradiation, a quantum system can undergo coherent (Rabi) oscillations in time. We report evidence for such oscillations in a _continuously_ observed three-Josephson-junction flux qubit, coupled to a high-quality tank circuit tuned to the Rabi frequency. In addition to simplicity, this method of_Rabi spectroscopy_ enabled a long coherence time of about 2.5 microseconds, corresponding to an effective qubit quality factor \~7000.