The EU-funded BRISQ project set out to explore how future quantum computers could run extremely long and complex calculations, far beyond what is possible today. Its overall aim was to lay the foundations for a quantum computing prototype capable of executing quantum algorithms with more than one million computational steps. Reaching such depths would represent a major advance in quantum information processing and simulation. In the long term, this could benefit applications where quantum computing is expected to play an important role, such as the design of new materials and pharmaceuticals, or the solution of complex optimization problems that require very deep calculations.
BRISQ focused on a novel technological approach based on trapped ions excited to very high-energy electronic states, known as Rydberg states. These so-called Rydberg ions interact strongly with each other over relatively long distances. A key advantage of this platform is that quantum information can remain stable for very long times - up to seconds - while quantum operations between ions can be carried out extremely quickly, within about 100 nanoseconds. This combination of long stability and fast operations is essential for enabling very deep and complex quantum computations.
At the start of BRISQ, research on Rydberg-ion quantum devices was being carried out in only two laboratories worldwide, both located in Europe. One partner in the BRISQ consortium had already demonstrated the first ultra-fast entangling operation using this approach, giving Europe a strong and unique position in developing this emerging technology. BRISQ built on this foundation by strengthening and expanding the scientific and technological basis of the platform.
To achieve its goals, BRISQ brought together a consortium of experimental and theoretical academic research groups alongside industrial partners. This broad range of expertise made it possible to address the challenge from many directions, from developing scalable and industry-compatible hardware to designing quantum algorithms and software tools tailored to this new technology. Together, these advances contribute to the long-term development of powerful quantum simulators and open new possibilities for applications such as the simulation of physical systems and, potentially, quantum chemistry.