Technology

We recently announced Project IDRA, the first phase of a 4-year project to pioneer an optically connected, multi-node distributed quantum computing system at the National Quantum Computing Centre in Harwell, UK. In this first phase we focus on addressing head-on the key technical barriers underpinning the quantum computing industry's biggest challenge: scaling. This project marks the beginning of a new scaling paradigm for quantum computing - from monolithic to distributed - enabled by weaving together modular and efficient QPUs using entanglement networks.

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Nu Quantum’s Platform for Networking Quantum Computers Hosted at the UK's National Quantum Computing Centre

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The first step to creating quantum computing networks is to efficiently connect qubits to the network. This requires quantum information to be transferred between the qubits that live inside a processor and the photons that make up the quantum optical network. Our Qubit-Photon Interfaces (QPIs) will enable 100x better entanglement rate than current lab state-of-the-art, and at an industrial scale. This technology is the quantum equivalent of today’s Network Interface Cards (NICs) in classical computing, which are used to interconnect computers inside datacentres and have enabled the development and growth of Cloud and AI markets.

Our QPI technology is based on optical microcavities, a well-understood tool for enhancing the interaction between matter and light. In this approach, nanostructured mirrors are placed around qubits to increased light-matter coupling and enable efficient light extraction. We fabricate ultrasmooth mirrors assembled with micron-level precision, with the distance between them actively stabilised to an accuracy of < 80 picometres using our "locking" technology.

Tuning the distance between microcavity mirrors with this level of precision is necessary to ensure to match the cavity resonance to each qubit's operational wavelength, boosting photon emission and entanglement rates. The cavity also ensures the shape of the emitted light beam can be efficiently coupled into an optical fibre, enabling easy connection to the quantum networking units.

We build custom QPIs for each qubit type, taking into account different material and performance requirements. Our technology is compatible with neutral atoms, trapped ions, solid-state qubits, and adaptable to other modalities. Our prototypes are already being validated by leading quantum computing companies inside their hardware systems.

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Qubit-Photon Interface (QPI): towards unlocking modular and scalable distributed quantum computing

https://spectrum.ieee.org/quantum-network-interface

Our proprietary photonic switching fabric combines waveguide-integrated optical components and superconducting nanowire detectors, capable of detecting single photons. We develop quantum-switching photonic chips that combine high performance and connectivity with low cross-talk, minimising fibre coupling and related losses, as well as shrinking the footprint of networking components. These photonic chips are designed to live inside our quantum networking units (QNUs), custom-built to support particular qubit wavelengths.

Combining tens to thousands of quantum processors into a larger computing architecture requires the development of Quantum Networking Units (QNUs), which distribute quantum entanglement across computing nodes. Our QNU unit represents an important first step to take quantum networking components from the laboratory and turning them into a deployable, industrialised prototype-product, capable of supporting test-bed integration with real qubits and software stacks.

We develop innovative networking solutions for distributed synchronisation and orchestration, as well as proprietary network protocols compatible with quantum computation and novel entanglement schemes for higher rates and fidelity. Our first-generation QNU is designed to support trapped-ion qubits in the first instance, but our modular approach enables upgradability of internal hardware to support different qubit modalities and their associated operational wavelengths.

We also lead a special-interest group of industry partners focused on Distributed Quantum Computing. With representation from quantum computing end-users, datacentre primes, and top qubit companies, we work to identify the performance specifications and capabilities required of the quantum and classical networking infrastructure necessary to deliver a scalable distributed computing fabric.

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Press release: Nu Quantum and Cisco Launch Pioneering Project to Create Modular and Scalable Quantum Network

The Quantum Insider: Nu Quantum and Cisco Launch Quantum Networking Project

Tech Monitor: Cisco announces new quantum networking collaboration with UK startup

Global Quantum Intelligence Quantum Computing Report: Nu Quantum and Cisco Partner to Develop Groundbreaking Modular Quantum Network Prototype

This approach represents a shift from QEC codes limited to local connections, opening new routes to fault-tolerance via modularity and distributed quantum entanglement. In early 2024, we started a collaboration with Canadian company softwareQ to develop the blueprint of a Modular Fault-Tolerant Quantum Computer, as part of a joint project funded by Innovate UK and the National Research Council of Canada.

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Press release: International collaboration will create theoretical blueprint for a Modular Fault-Tolerant Quantum Computer