Low-crosstalk bifurcation detectors for coupled flux qubits

TL;DR

This paper demonstrates low-crosstalk bifurcation detectors for coupled flux qubits, achieving high-fidelity readout with minimal measurement correlation, advancing multi-qubit quantum information experiments.

Contribution

It introduces a method to reduce crosstalk in bifurcation detectors for flux qubits, enabling more reliable multi-qubit measurements.

Findings

Measured crosstalk of 0.1% with proper phase tuning

Correlation between measurement outcomes less than 0.05%

Bifurcative readout is effective for multi-partite correlation experiments

Abstract

We present experimental results on the crosstalk between two AC-operated dispersive bifurcation detectors, implemented in a circuit for high-fidelity readout of two strongly coupled flux qubits. Both phase-dependent and phase-independent contributions to the crosstalk are analyzed. For proper tuning of the phase the measured crosstalk is 0.1 % and the correlation between the measurement outcomes is less than 0.05 %. These results show that bifurcative readout provides a reliable and generic approach for multi-partite correlation experiments.