Although single and two-qubit gates are sufficient for universal quantum computation, single-shot three-qubit gates greatly simplify quantum error correction schemes and algorithms. We design fast, high-fidelity three-qubit entangling gates based on microwave pulses for transmon qubits coupled through a superconducting resonator. We show that when interqubit frequency differences are comparable to single-qubit anharmonicities, errors occur primarily through a single unwanted transition. This feature enables the design of fast three-qubit gates based on simple analytical pulse shapes that are engineered to minimize such errors. We show that a three-qubit ccz gate can be performed in 260 ns with fidelities exceeding 99.38%, or 99.99% with numerical optimization.
@article{arxiv.1612.09384,
title = {Fast microwave-driven three-qubit gates for cavity-coupled superconducting qubits},
author = {Edwin Barnes and Christian Arenz and Alexander Pitchford and Sophia E. Economou},
journal= {arXiv preprint arXiv:1612.09384},
year = {2017}
}