10126425FATCAT – Real-time quantum error correction for FAult-Tolerant CAT-based quantum computersActiveCollaborative R&DInnovate UKQuantum computers are a new type of computational tool with the potential to completely transform critical industries such as healthcare, manufacturing, and finance. Their building blocks, called qubits, can process information in a highly effective way, allowing execution of computations that are much more complex and fast than classical computers. However, qubits are significantly more sensitive to disturbance from the environment: such noise causes at least one error every one thousand operations in current quantum computers, undermining their reliability. To overcome this problem, we can adopt quantum error correction techniques that use multiple qubits to "encode" the information on multiple qubits in such a way that it can be retrieved or "decoded", even if some of the qubits are disturbed by noise. A key research goal is to develop the best qubit architectures and error correction techniques that allow us to achieve reliable computational results without requiring a massive number of qubits. In addition, the coding and decoding processes must be performed continuously and at high speed by the quantum computer, while it executes the useful computations we are interested in. This project brings together leading quantum computing companies from the UK and France -- Riverlane and Alice&Bob -- and an academic group from CEA-LETI in France, to address this challenge. Alice&Bob will optimise a highly advanced type of qubit, called Schrödinger's cat qubits, that are able to self-correct some of the errors induced by environmental noise. They can further suppress the remaining errors using error-correction schemes that have been used in other common applications like 5G communications. CEA-LETI and Riverlane will optimise these error-correction schemes and the related decoding processes to improve the execution speed while preserving a very high computational accuracy. Moreover, Riverlane will use fast electronic components to further speed up the execution of the decoding processes and integrate them closely with the cat qubits. In this way, the time from the occurrence of an error to its identification and correction will be as fast as one microsecond. This will allow the quantum computer to execute all the building blocks effectively to run a complex calculation. The improvements demonstrated in this project will represent a crucial step towards the development of the quantum computers that can simulate the new molecules, chemical processes and drugs that will help combat climate change, develop precision medicine and boost clean energy production in the near future.