Jülich researchers are combining quantum computers with supercomputers. Such hybrid systems are intended to unite the advantages of both worlds and crack previously unsolvable scientific puzzles.
Supercomputers and quantum computers work completely differently. You could say that one is a traditionalist, one a revolutionary. Supercomputers perform reliable calculations according to the familiar rules of physics using ones and zeros. Quantum computers, on the other hand, come from the bizarre world of quantum physics: they use all numbers between one and zero, and are capable of an unimaginable amount at the same time – but they are still difficult to control.
In future, these unequal computing masters will work together as a power duo at Jülich. One such hybrid system is formed by the established JURECA DC supercomputer and JADE, a 100-qubit quantum simulator delivered by French company Pasqal, which has been in operation at the Jülich Supercomputing Centre (JSC) since the end of 2024. Others are set to follow, including the new exascale supercomputer JUPITER, which is currently being built at Jülich. JUPITER will be coupled with the D-Wave Advantage2 system, an annealing quantum computer recently acquired for the Jülich UNified Infrastructure for Quantum computing (JUNIQ) (see infobox, page 30). This duo creates new opportunities for breakthroughs in artificial intelligence and optimization, for example in the field of logistics. Such hybrid systems are also expected to find answers to some of the trickiest questions in modern science, such as modelling complex climate scenarios or the structures of giant molecules.
We want to combine the advantages of both systems. The supercomputer does most of the work and ensures a stable workflow. The quantum computer steps in whenever its partner gets stuck or takes too long to solve the problem.
The best of both worlds
“We want to combine the advantages of both systems,” explains Prof. Kristel Michielsen from JSC. “The supercomputer does most of the work and ensures a stable workflow. The quantum computer steps in whenever its partner gets stuck or takes too long to solve the problem.” One example would be climate simulations: “The supercomputer performs the central modelling, while the quantum computer takes on specific subtasks such as highly complex optimization questions.” This could involve investigating atmospheric chemistry, for example, where the multitude of chemical particles and processes means that there is a huge number of possibilities to be tested.
As such modelling involves countless parameters, this would keep even the most powerful supercomputers – such as the new exascale computer JUPITER – busy for years or even decades. This is not the case with quantum computers. Unlike conventional bits, their computing units, qubits, can not only assume the values 0 and 1, but also any number of values in between. A quantum processor therefore has the potential to perform numerous operations in parallel, which is why it could calculate significantly faster and more efficiently than a conventional computer. “This saves time and energy,” says Michielsen.
JSC has already connected a small five-qubit system from German–Finnish manufacturer IQM to its JURECA DC supercomputer and carried out initial test experiments. A superconducting qubit system developed by Jülich researchers in collaboration with Goethe University Frankfurt and the companies ParTec and Quantum Machines will soon be added, as well as an ion trap system from the German start-up eleQtron. All three systems will be integrated into JSC’s supercomputing infrastructure and are part of the JUNIQ user infrastructure, where FZJ combines, develops, and tests a wide variety of quantum systems. “JUNIQ offers users the unique opportunity to find the most suitable quantum system for their needs and compare different concepts on a single platform,” stresses Michielsen.
To allow the quantum computers to fully leverage their strengths at the right moments, researchers first need to coordinate the communication and methodology of the two different types of computers. This requires software that takes into account both traditional and quantum mechanical approaches. If all this succeeds, the hybrid systems could answer important questions not only in climate research, but also in chemistry, medicine, materials science, finance, AI research, logistics, and quantum physics. Therefore, when it comes to major scientific challenges, it could prove to be a great advantage to have two systems cooperating that work in completely different ways.
Extensive expertise
Forschungszentrum Jülich’s broad expertise in supercomputing and quantum computing really comes to the fore with the development of such hybrid computers on the Jülich campus. Back in 1987, the Jülich Supercomputing Centre (JSC) was the first high-performance computing centre in Germany. Now, the first European exascale computer, JUPITER, is being built there. “Exa” denotes a “1” with 18 zeros, or a quintillion calculations per second. This is roughly equivalent to the computing power of 1 million modern smartphones. The Jülich supercomputer community also includes four other supercomputers.
Jülich’s quantum research is also unique in Germany. The scientists cover the entire spectrum of quantum research – from quantum theory, hardware construction, and software programming to the testing and further development of finished components. Depending on the problem at hand, the researchers work with very different systems, each with their own characteristics – including a quantum annealer from the Canadian company D-Wave. This makes it possible to try out different techniques and power duos at Jülich.
This text is taken from the 1/25 issue of effzett. Text: Janosch Deeg; Images: Forschungszentrum Jülich/Sascha Kreklau
