Compilation and scaling strategies for a silicon quantum processor with sparse two-dimensional connectivity

Abstract

Inspired by the challenge of scaling-up existing silicon quantum hardware, we propose a 2d spin-qubit architecture with low compilation overhead. The architecture is based on silicon nanowire split-gate transistors which form 1d chains of spin-qubits and allow the execution of two-qubit operations among neighbors. We introduce a silicon junction which can couple four nanowires into 2d arrangements via spin shuttling and Swap operations. We then propose a modular sparse 2d spin-qubit architecture with unit cells of diagonally-oriented squares with nanowires along the edges and junctions on the corners. Targeting noisy intermediate-scale quantum (NISQ) demonstrators, we show that the proposed architecture allows for compilation strategies which outperform methods for 1d chains, and exhibits favorable scaling properties which enable trading-off compilation overhead and colocation of control electronics within each square by adjusting the nanowire length. An appealing feature of the proposed architecture is its manufacturability using complementary-metal-oxide-semiconductor (CMOS) fabrication processes.