Fast Measurement of a Tunable Superconducting Flux Qubit via a Driven Nonlinear Resonator with Applications in Quantum Annealing

Development of readout schemes of flux qubits in the persistent current basis is important for quantum annealing applications. High fidelity detection, controlled backaction on the qubit, as well as rapid acquisition, are all relevant for flexible quantum annealing. In order to accommodate these requirements, we develop a readout based on the use of metastable oscillation states in a nonlinear oscillator detection circuit specifically tailored for capacitively shunted flux qubits. In this work, we discuss the design as well as preliminary results for a device specifically designed for tunable capacitively shunted flux qubits specifically designed for use in quantum annealers.

This material is based upon work supported by the Intelligence Advanced Research Projects Activity (IARPA) and the Army Research Office (ARO) under Contract No. W911NF-17-C-0050. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Intelligence Advanced Research Projects Activity (IARPA) and the Army Research Office (ARO).