We present a scalable scheme for executing the error-correction cycle of a monolithic surface-code fabric composed of fast-flux-tuneable transmon qubits with nearest-neighbor coupling. An eight-qubit unit cell forms the basis for repeating both the quantum hardware and coherent control, enabling spatial multiplexing. This control uses three fixed frequencies for all single-qubit gates and a unique frequency detuning pattern for each qubit in the cell. By pipelining the interaction and readout steps of ancilla-based X- and Z-type stabilizer measurements, we can engineer detuning patterns that avoid all second-order transmon-transmon interactions except those exploited in controlled-phase gates, regardless of fabric size. Our scheme is applicable to defect-based and planar logical qubits, including lattice surgery.
@article{arxiv.1612.08208,
title = {Scalable quantum circuit and control for a superconducting surface code},
author = {R. Versluis and S. Poletto and N. Khammassi and N. Haider and D. J. Michalak and A. Bruno and K. Bertels and L. DiCarlo},
journal= {arXiv preprint arXiv:1612.08208},
year = {2017}
}