Multicore Quantum Computing

TL;DR

This paper investigates scalable multicore quantum computing architectures, focusing on semiconductor electron spin systems, modeling interlinks, and proposing entanglement purification to achieve high-fidelity communication for quantum advantage.

Contribution

It introduces analytic and numerical models for multicore architectures, evaluates interlink fidelities, and proposes optimized entanglement purification to enable high-fidelity quantum communication.

Findings

Achievable interlink fidelities are promising but lower than intra-core operations.

Optimized entanglement purification can reach 99.5% fidelity.

Error mitigation schemes effectively suppress imperfections in multicore systems.

Abstract

Any architecture for practical quantum computing must be scalable. An attractive approach is to create multiple cores, computing regions of fixed size that are well-spaced but interlinked with communication channels. This exploded architecture can relax the demands associated with a single monolithic device: the complexity of control, cooling and power infrastructure as well as the difficulties of cross-talk suppression and near-perfect component yield. Here we explore interlinked multicore architectures through analytic and numerical modelling. While elements of our analysis are relevant to diverse platforms, our focus is on semiconductor electron spin systems in which numerous cores may exist on a single chip. We model shuttling and microwave-based interlinks and estimate the achievable fidelities, finding values that are encouraging but markedly inferior to intra-core operations. We therefore introduce optimsed entanglement purification to enable high-fidelity communication, finding that $99.5\%$ is a very realistic goal. We then assess the prospects for quantum advantage using such devices in the NISQ-era and beyond: we simulate recently proposed exponentially-powerful error mitigation schemes in the multicore environment and conclude that these techniques impressively suppress imperfections in both the inter- and intra-core operations.