A €10m project in Germany is aiming to build a quantum computer with several hundred qubits using photonics.
Supercooled quantum computers currently have a handful of qubits, and are looking at ways to put thousands of these on a chip. However startups such as PsiQuantum are aiming to use photonics at room temperature to build more massive quantum computer.
The QRydDemo project, led by the University of Stuttgart and part of the 'Built in Germany' research scheme, aims to build a photonic quantum computer with several hundred qubits in the next four years using Rydberg atoms. These are highly excited atoms where the outermost electron is extremely far away from the atomic core. This makes the atoms up to 10,000 times larger than that of an atom in ground state, but unlike an ion, the outer electron is not free but still bound to the atomic core, albeit extremely weakly. This means it reacts sensitively to external electromagnetic stimuli and interacts strongly and controllably with neighbouring Rydberg atoms. This behaviour can be used to build fast quantum logic gates, and the project wants to bring this technique to a stage where it can directly compete with other established quantum computing platforms and be offered to customers on the market.
Industrial partner Toptica Photonics is aiming to develop low-noise high-power lasers for single-atom traps to enable quantum registers with long coherence time. These also need ultra-low phase noise to perform quantum gate operations with high fidelity, and this combination is not available on the market.
“Toptica emerged about 25 years ago from academic research in quantum optics, which has now evolved into quantum technology,” said Dr. Juergen Stuhler, Vice President Quantum Technologies at Toptica. “Many of our employees have had an academic career in this field and most of our customers are involved in quantum technology. Thus, fascination and enthusiasm for the