Europe’s largest sampling-based photonic quantum computer is operational

Researchers at Paderborn University in Germany have successfully set up Europe’s largest sampling-based photonic computer. Dubbed Paderborn Quantum Sampler (PaQS), the quantum computer has been built as part of an initiative by the Federal Ministry of Education and Research (BMBF), in partnership with private firms.

Referred to as the next frontier of computing, quantum computers present an opportunity to complete complex calculations in a fraction of the time the world’s fastest silicon-based supercomputers will take. This could help solve complex problems of the real world – ranging from drug discovery to manufacturing, logistics to finance.

Quantum computers can achieve this using properties of quantum mechanical effects such as quantum entanglement and superposition. However, these approaches are highly sensitive and can rapidly accumulate errors. Researchers worldwide are experimenting with different platforms to reduce the imperfections of quantum computer systems. One such approach is photonic quantum computers.

The German approach

As the name suggests, photonic quantum computers use photons or light particles to perform computational work. The technology has been maturing rapidly in recent years since photon-based quantum computers can operate at room temperature, making them easier to work with.

However, the system also has a disadvantage. As with other light-based systems, it is prone to optical losses. Researchers at Paderborn University turned to their in-house expertise in working with photonic systems to build a quantum computer not plagued by optical losses.

To do so, the research team built Europe’s largest Gaussian boson sampling machine with PaQS to understand where photons leave the quantum network and find ways to fix the issue.

What is Gaussian boson sampling?

Researchers have previously used Gaussian boson sampling as a photonic computing model for building quantum computers. However, on this occasion, the team used a forward-looking approach, keeping system integration and programmability in mind.

Explaining their approach in a press release, Christine Silberhorn, a physicist at the Institute of Photonic Quantum Systems at Paderborn University, said that the team used a programmable interferometer in their experiments to integrate any configuration of their choice.

“With this approach, light particles are distributed and directed within a network of fibre optic cables – a little like the network of switches in a shunting yard. At the output of the network, the location where the photons emerge is measured,” Silberhorn explained.

The advantage of full programmability will allow researchers to use the system for quantum computing applications that might develop in the future. “This can, for example, be relevant for solving protein folding problems or calculating certain molecular states as part of pharmaceutical research,” Silberhorn added in the press release .

The research team applied their expertise in quantum mechanics phenomena such as squeezing and photon entanglement, through which quantum mechanical properties can be manipulated and harnessed.

Yet developing the PaQs required the development of multiple new components. This was achieved in partnership with Menlo Systems, Fraunhofer IOF Jena, and Swabian Instruments and coordinated by Q.ANT, a German company with expertise in industrial quantum technologies.

The collaboration will soon install a sampling-based quantum computer that will also be accessible via the cloud .