A fault-tolerant continuous-variable measurement-based quantum computation architecture

TL;DR

This paper presents a scalable, fault-tolerant architecture for continuous-variable measurement-based quantum computation using 3D cluster states, GKP codes, and surface codes, validated through simulations showing a 12.7 dB squeezing threshold.

Contribution

It introduces a complete, scalable fault-tolerant architecture integrating cluster state generation, gate teleportation, and error correction with realistic noise models.

Findings

Fault-tolerant squeezing threshold of 12.7 dB.

Efficient implementation with as few as two squeezed light sources.

Supports topological and GKP error correction within the architecture.

Abstract

Continuous variable measurement-based quantum computation on cluster states has in recent years shown great potential for scalable, universal, and fault-tolerant quantum computation when combined with the Gottesman-Kitaev-Preskill (GKP) code and quantum error correction. However, no complete fault-tolerant architecture exists that includes everything from cluster state generation with finite squeezing to gate implementations with realistic noise and error correction. In this work, we propose a simple architecture for the preparation of a cluster state in three dimensions in which gates by gate teleportation can be efficiently implemented. To accommodate scalability, we propose architectures that allow for both spatial and temporal multiplexing, with the temporal encoded version requiring as little as two squeezed light sources. Due to its three-dimensional structure, the architecture supports topological qubit error correction, while GKP error correction is efficiently realized within the architecture by teleportation. To validate fault-tolerance, the architecture is simulated using surface-GKP codes, including noise from GKP-states as well as gate noise caused by finite squeezing in the cluster state. We find a fault-tolerant squeezing threshold of 12.7 dB with room for further improvement.