The mission of the Quantum Internet Alliance (QIA) is to build a global Quantum Internet made in Europe – by developing a full-stack prototype network, and by driving an innovative European Quantum Internet ecosystem capable of scaling the network to worldleading European technology. Building on its proven track record in teamwork, which has already resulted in world first Quantum Internet technology, QIA advances this mission in two complementary objectives: The first is the realization of a full-stack prototype network able to distribute entanglement between two metropolitan-scale networks via a long-distance backbone (>500 km) using quantum repeaters. The second is the establishment of a European platform for Quantum Internet development, which will act as a catalyst for a European Quantum Internet Ecosystem including actors all along the value chain. QIA’s network will enable advanced quantum-network applications and prepare the ground for secure quantum computing in the cloud, thanks to our new generation of end nodes including both processing nodes and low-cost photonic client devices. Nodes in the metropolitan network will be interconnected via hubs that allow the scalable connection of hundreds of end nodes, paving the way for early adopters. The long-distance backbone will be realized using fully functional quantum repeaters unlocking Pan-European end-to-end quantum communication. QIA’s prototype network will operate on standard optical fibers and serves to validate all key sub-systems, ready to be scaled by European industry. In this first SGA we will advance towards the long-term objectives set up in the FPA project. Here we present in detail how work will be implemented during this first phase of the SGA.

This project focuses on scalability, availability, and applicability aspects of trapped-ion quantum computers, tackling the transition from current laboratory-based experiments to industry-grade quantum computing technologies. This project will provide the technological framework for quantum computers to solve real-world problems inaccessible to current classical computers. Taking advantage of the unrivalled low error rates of operations available in trapped-ion quantum processors today, we will develop a fully connected 50-qubit device, allowing the implementation of calculations that are out of the reach of classical computers. The system will enable straightforward high-level user access via a robust hardware and software stack, allowing remote execution of complex algorithms without hardware-specific knowledge. We will pave the way to large-scale and fault-tolerant quantum computing by introducing long-range connectivity via ion-shuttling between sub-processors and by establishing remote operations between quantum processors using photonic interconnects. These scalable techniques will make systems exceeding thousands of qubits possible, in combination with error correction and entanglement purification techniques. Within this project, we will combine these quantum information techniques with trap fabrication and packaging technologies which integrate optical and electronic components to achieve stable long-term operation in an industrial environment. These scientific and technological advances will provide a powerful platform to demonstrate trapped-ion quantum computers capable of solving problems of major commercial importance including computational problems in chemistry and machine learning.

The MILLENION project focuses on modular scalability and accessibility aspects of trapped-ion quantum computers (QCs), tackling the transition from current laboratory-based experiments to industry-grade quantum computing technologies with technology readiness level above 8. The envisaged platform, which builds on top of the rack-mounted 50-qubit QC demonstrator realised in the flagship project AQTION, will offer a quantum advantage for various use-cases in a fully automated 100-qubit ion-trap QC. Our consortium will aggressively pursue disruptive development goals: (a) changing from one-dimensional strings of ions to two-dimensional arrays will allow us to support up to100 qubits; (b) consistently encoding quantum information in the electronic ground state of ion qubits enables error rates smaller than 10-3 per gate operation compatible with fault-tolerant error correction; and (c) implementing parallel gate operations will enable larger algorithmic depth. The new demonstrator devices will be equipped with a hardware-optimised firmware suite and will be integrated in a high-performance computing (HPC) infrastructure to realise a QC/HPC solution, supporting standardised interfaces to various quantum software development kits with cloud accessibility. Finally, we will pave the way to scalable quantum computing by introducing long-range connectivity between quantum processors. We will combine these quantum information techniques with trap fabrication and packaging technologies which integrate optical and electronic components to achieve stable long-term operation in an industrial environment. These scientific and technological advances will provide a powerful hardware platform that can be exploited by partnering quantum software Within this project, the ion-trap quantum computing platform will be extended to push towards 100 qubits, realize fault-tolerant performance levels, and pursue the demonstration of a European quantum advantage.

This Fellowship application will provide support for a leading Photonics Engineering Academic, Prof Peter Smith, University of Southampton, to build a research team to address industry and academic led challenges in Quantum Technologies. The project is entitled QuINTESSEnCE - standing for Quantum Integrated Nonlinear Technology Enabling Stable, Scaleable Engineered for Commercial Exploitation. This title reflects our desire to develop technology that will be stable and applicable in real-world applications, and move that towards developing a supply chain to take Quantum Technologies towards commercial reality. The work will focus on building optical components and photonic manufacturing capability for the next generation of science and, by working closely with companies, to provide the components needed to underpin the application of quantum enabled technology to address a wide range of societal and economic challenges. Two core technologies will be developed, the first being lasers that are exceptionally stable and low noise, and ideally suited for use in a wide range of science applications. The second technology will see the development of new optical materials capable of converting the wavelength (colour) of laser light, efficiently and cheaply. The approach will use high reflecting cavities to enhance the light fields, giving high conversion efficiency and, importantly, exploiting the laws of quantum science to create photons with unique properties. The highlight of the project will be manufacturing demonstrators of our quantum enabled optical technology to take to companies and end-users that will act to prove their value. Two demonstration areas are planned, firstly detectors that will be able to see extremely low light levels in the infra-red without the need for expensive cooling to prevent noise. The second will be to use our lasers and cavities to show advantage in measuring optical fibre links while they are in use, improving data reliability on the internet and increasing down-load speeds. Detectors and other devices will be based on fundamental quantum properties, in which two photons can be fused together to create a single photon with higher energy but preserving fundamental quantum information in the photons themselves.

The future Quantum Internet will provide radically new internet applications by enabling quantum communication between any two points on Earth. The Quantum Internet Alliance (QIA) targets a Blueprint for a pan-European Quantum Internet by ground-breaking technological advances, culminating in the first experimental demonstration of a fully integrated network stack running on a multi-node quantum network. QIA will push the frontier of technology in both end nodes (trapped ion qubits, diamond NV qubits, neutral atom qubits) and quantum repeaters (rare-earth-based memories, atomic gases, quantum dots) and demonstrate the first integration of both subsystems. We will achieve entanglement and teleportation across three and four remote quantum network nodes, thereby making the leap from simple point-to-point connections to the first multi-node networks. We will demonstrate the key enabling capabilities for memory-based quantum repeaters, resulting in proof-of-principle demonstrations of elementary long-distance repeater links in the real-world, including the longest such link worldwide. Hand in hand with hardware development, we will realize a software stack that will provide fast, reactive control and allow arbitrary high-level applications to be realized in platform-independent software. QIA's industry partners examine real world use cases of application protocols and their hardware requirements. We will validate the full stack on a small Quantum Internet by performing an elementary secure delegated quantum computation in the cloud. We will validate the design of the Blueprint architecture by a large-scale simulation of a pan-European Quantum Internet using real world fibre data. Through synergy of leading industrial, academic and RTO partners, QIA's Blueprint will provide a targeted roadmap for the main Flagship phase and set the stage for a world-leading European Quantum Internet industry.