Weak continuous monitoring of a flux qubit using coplanar waveguide resonator

TL;DR

This paper demonstrates weak continuous monitoring of a flux qubit via a coplanar waveguide resonator, achieving intermediate coupling for dispersive readout with minimal backaction, supported by theoretical analysis and experimental data.

Contribution

It introduces a method for weak, continuous flux qubit measurement using a coplanar waveguide resonator in the intermediate coupling regime, with detailed theoretical and experimental validation.

Findings

Achieved intermediate coupling regime for flux qubit measurement.

Dispersive readout with weak backaction on the qubit.

Good agreement between theory, simulation, and experimental data.

Abstract

We study a flux qubit in a coplanar waveguide resonator by measuring transmission through the system. In our system with the flux qubit decoupled galvanically from the resonator, the intermediate coupling regime is achieved. In this regime dispersive readout is possible with weak backaction on the qubit. The detailed theoretical analysis and simulations give a good agreement with the experimental data and allow to make the qubit characterization.