Demonstration of Universal Parametric Entangling Gates on a Multi-Qubit Lattice

We show that parametric coupling techniques can be used to generate selective entangling interactions for multi-qubit processors, and in such a way that is scalable. By inducing coherent population exchange between adjacent qubits under frequency modulation, we implement a universal gateset for a linear array of eight superconducting qubits. We establish the suitability of this technique by doing an error analysis on our two-qubit gate fidelity (via QPT), and by preparing an eight-qubit register in all possible bitstring permutations and monitor the fidelity of a two-qubit gate across one pair of these qubits. These results thus offer a path to a scalable architecture with high selectivity and low crosstalk.