2017/06/30 by M. Reagor, C. B. Osborn, N. Tezak +56 · 1 citation
Physics and Astronomy · #quant-ph #cond-mat.mes-hall
paper · pdf · doi:10.1126/sciadv.aao3603
published as Science Advances 02 Feb 2018: Vol. 4, no. 2, eaao3603
arxiv created 2018/02/27 · arxiv updated 2018/02/28
We show that parametric coupling techniques can be used to generate selective entangling interactions for multi-qubit processors. By inducing coherent population exchange between adjacent qubits under frequency modulation, we implement a universal gateset for a linear array of four superconducting qubits. An average process fidelity of F=93% is estimated for three two-qubit gates via quantum process tomography. We establish the suitability of these techniques for computation by preparing a four-qubit maximally entangled state and comparing the estimated state fidelity against the expected performance of the individual entangling gates. In addition, we prepare an eight-qubit register in all possible bitstring permutations and monitor the fidelity of a two-qubit gate across one pair of these qubits. Across all such permutations, an average fidelity of F=91.6±2.6% is observed. These results thus offer a path to a scalable architecture with high selectivity and low crosstalk.