Scalable quantum computing with continuous variable cluster states

Introduction

Measurement-based quantum computation is a highly promising approach to quantum computing as it simply performs quantum processing directly through the measurements of a multi-partite entangled cluster state and thereby circumvents the complex unitary dynamics of conventional gate-based quantum computers.

Challenges

However, despite significant progress over the last decade in devising new strategies for measurement-based quantum computing, significant conceptual and technical challenges still remain for realizing up-scaled versions that reach the quantum advantage regime where it outperforms classical computation.

Objectives of ClusterQ

In ClusterQ, we aim to overcome these challenges using continuous variable three-dimensional entangled cluster states. Based on our recent work on generating and exploiting extremely large two-dimensional cluster states, we aim to make conceptual breakthroughs along three different directions:

1. Scalable Cluster States: We deterministically generate highly scalable three-dimensional cluster states of different topological structures and explore their many-body behaviour and usefulness for quantum computing.

2. Quantum Boson Sampling Algorithms: We use the three-dimensional cluster states combined with hybrid detection technologies to demonstrate new quantum boson sampling algorithms – a near-term quantum computing algorithm allowing for a demonstration of quantum computational supremacy.

3. Fault-Tolerant Measurement-Based Quantum Computation: Finally, we explore, theoretically and experimentally, a novel strategy for fault-tolerant measurement-based quantum computation using surface codes in 3D cluster states.

Long-Term Goals

ClusterQ aims to position the continuous variable measurement-based approach to quantum information processing in the field of front-running candidates for NISQ (noisy, intermediate-scale quantum) computing and, in the longer term, fault-tolerant quantum computing.