A supercomputer in Germany has done something no machine has ever done before: it fully simulated a 50-qubit quantum computer. The feat, carried out on Europe's first exascale supercomputer named JUPITER, shatters the prior world record of 48 qubits set by the same research team in 2019 using a Japanese system.
Why simulating a quantum computer matters
Researchers at the Jülich Supercomputing Centre, working with NVIDIA, ran the simulation to test algorithms and explore how future quantum systems will behave. Real quantum hardware is not yet powerful enough to handle many of these tasks. Simulations let scientists validate experimental results and develop new algorithms before the machines exist to run them. Two algorithms of particular interest are the Variational Quantum Eigensolver, used to study molecules and materials, and the Quantum Approximate Optimisation Algorithm, which tackles optimization problems in logistics, finance, and artificial intelligence.
The staggering difficulty of the calculation
Simulating a quantum computer on a classical machine is brutally hard because each additional qubit doubles the required memory and computing power. A standard laptop can handle roughly 30 qubits. For 50 qubits, the simulation needed about 2 petabytes of memory, or roughly two million gigabytes. Only the world's largest supercomputers can provide that much. Every operation, such as applying a quantum gate, affects more than 2 quadrillion numerical values, a 2 followed by 15 zeros. Those values must stay synchronized across thousands of computing nodes to accurately mimic a real quantum processor.
JUPITER, Europe's first exascale supercomputer, was officially launched at Forschungszentrum Jülich in September 2025. The system relies on NVIDIA GH200 Superchips, which tightly connect central processing units and graphics processing units. This design allows data that exceeds GPU memory to be temporarily stored in CPU memory without losing performance.
What this means for quantum research
Professor Kristel Michielsen, Director at the Jülich Supercomputing Centre, noted that this use case shows how closely progress in high-performance computing and quantum research are intertwined today. The breakthrough does not replace the need for real quantum hardware, but it gives scientists a powerful tool to develop and test quantum algorithms now. It also demonstrates that classical supercomputers, when pushed to their limits, can still extend the frontier of quantum research.
