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arXiv · 1905.05670

Calibration of the cross-resonance two-qubit gate between directly-coupled transmons

A. D. Patterson·J. Rahamim·T. Tsunoda·P. Spring·S. Jebari·K. Ratter·M. Mergenthaler·G. Tancredi·B. Vlastakis·M. Esposito·P. J. Leek
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Abstract

Quantum computation requires the precise control of the evolution of a quantum system, typically through application of discrete quantum logic gates on a set of qubits. Here, we use the cross-resonance interaction to implement a gate between two superconducting transmon qubits with a direct static dispersive coupling. We demonstrate a practical calibration procedure for the optimization of the gate, combining continuous and repeated-gate Hamiltonian tomography with step-wise reduction of dominant two-qubit coherent errors through mapping to microwave control parameters. We show experimentally that this procedure can enable a $\hat{ZX}_{-\pi/2}$ gate with a fidelity $F=97.0(7)\%$, measured with interleaved randomized benchmarking. We show this in a architecture with out-of-plane control and readout that is readily extensible to larger scale quantum circuits.

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A. D. Patterson, J. Rahamim, T. Tsunoda, P. Spring, S. Jebari, K. Ratter, M. Mergenthaler, G. Tancredi, B. Vlastakis, M. Esposito, P. J. Leek. 2019-05-14. Calibration of the cross-resonance two-qubit gate between directly-coupled transmons. https://doi.org/10.1103/physrevapplied.12.064013

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