Bigger is better
Quantum computers promise to solve certain problems that are out of reach for even the most powerful conventional computers. But turning that promise into practical technology requires overcoming one of the field’s biggest challenges: scalability.
Today’s quantum computers are still relatively small and experimental. Future machines will need vastly larger numbers of quantum bits – or qubits – to tackle useful real-world problems. One way of reaching that scale is to build a single enormous processor. Another is to connect many smaller processors so they can work together as one system.
That is the approach being pursued by PHOTONIQC, a new European research project focused on distributed quantum computing using photons, the smallest particles of light.
Rather than trying to put all the necessary qubits into one machine, the project will develop the technologies needed to link multiple quantum processors into a network.
Light as a carrier
Photons are particularly promising for distributed quantum computing because they can carry quantum information from one place to another. This could allow separate quantum processors to communicate and work together without having to be physically integrated into a single device.
But making that vision a reality requires several technological pieces to work together.
The PHOTONIQC consortium will develop highly efficient light sources that can produce individual photons on demand, photonic chips that can guide and manipulate light with very low losses, and advanced detectors capable of efficiently detecting single photons. The project will also develop new protocols for processing and communicating quantum information across a network.
Together, these technologies could provide the building blocks for larger photonic quantum computers.
The ambition is not simply to improve individual components, but to demonstrate how they can work together as part of a distributed system. Over the next four years, the project aims to produce new generations of high-performance quantum photonic components and carry out some of Europe's first experimental demonstrations of distributed photonic quantum computing.
A European effort
PHOTONIQC brings together universities, research institutes and companies from across Europe. The collaboration builds on Europe's strong position in photonic quantum technologies, while aiming to strengthen its ability to develop complete quantum computing systems.
The project also has a strong focus on training. 15 doctoral candidates will work across the network, gaining expertise in areas ranging from single-photon sources, low-loss photonic chips, advanced photon detectors, and new quantum computing protocols.
The aim is to create not only new technologies, but also the people needed to develop them further.
This is particularly important as quantum technology moves from fundamental research towards commercial development. Skilled researchers and engineers will be needed to turn advances in the laboratory into technologies that can eventually be used by industry and society.
From the lab to real-world applications
Quantum computers are still an emerging technology, and many potential applications remain years away. But if scalable quantum computers can be built, they could open up new possibilities in areas where conventional computers struggle.
Potential applications include accelerating the development of medicines and materials, improving energy technologies and optimising complex logistics and industrial systems.
PHOTONIQC is focused on a more fundamental challenge that comes first: building the technological foundations that could make such applications possible.
The result could be an important step towards quantum computers that are not just powerful in the laboratory, but scalable enough to tackle problems beyond the reach of today's computers.
