University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Colloquium

Thursday, September 12th 2019
3:35 pm:
Speaker: Vadim Smelyanskiy, Google, Los Angeles
Subject: Fast quantum logical gates for tunable superconducting qubits

We present theoretical results and experimental demonstration of high-fidelity diabatic two-qubit quantum logical gates with fidelities up to 0.9966 for gate times as short as 1.2 times the speed limits. This is achieved by synchronizing the tunable entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iSWAP-like and CPHASE gates with cross-entropy benchmarking. We discuss the realization of such calibration on two alternative architectures with fixed and tunable qubit-qubit coupling respectively. We construct the effective theory of the system with tunable coupling and use it to design and implement a similar set of diabatic gates. The presented approach can be extended to multibody operations as well.

Faculty Host: Alex Kamenev

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