Jülich Simulates a 50-Qubit Quantum Computer on an Exascale Supercomputer
22 Nov 2025 – Researchers at Forschungszentrum Jülich have fully simulated a universal 50-qubit quantum computer using Europe’s first exascale supercomputer, JUPITER. This achievement, requiring on the order of 2 petabytes of memory, breaks the previous simulation record of 48 qubits set in 2019 and provides a powerful new testbed for quantum algorithms. It marks a milestone intertwining high-performance computing (HPC) with quantum research, showing how advances in exascale systems can push quantum experimentation beyond current hardware limitations.
How was this made possible? The JUPITER supercomputer is powered by NVIDIA’s GH200 “Grace Hopper” Superchips, which tightly integrate CPUs and GPUs with unified memory access. By enhancing the Jülich Universal Quantum Computer Simulator (JUQCS) to exploit this hybrid memory, the team could offload data to CPU memory when it exceeded GPU memory limits with minimal performance loss. They also implemented an on-the-fly compression technique that reduced memory needs eightfold, and a dynamic algorithm to efficiently synchronize computations across more than 16,000 GH200 nodes. These innovations allowed the simulation to handle the staggering $2^{50}$ complex amplitudes (over 2 quadrillion values) that describe a 50-qubit state.
Why is this important? Simulating quantum processors on classical supercomputers is crucial for validating quantum algorithms and exploring quantum phenomena in regimes where real hardware is not yet available. At 50 qubits, the simulation approaches the cusp of what’s classically feasible – a typical laptop can barely handle ~30 qubits, since each added qubit doubles the memory and compute required. Reaching 50 qubits on JUPITER underscores how progress in HPC enables deeper quantum research: “This use case illustrates how closely progress in high-performance computing and quantum research are intertwined today,” noted Prof. Kristel Michielsen of JSC. The simulated 50-qubit platform can now serve as a high-fidelity benchmark to test quantum algorithms like variational chemistry solvers (VQE) or optimization routines (QAOA) against ideal outcomes. In the words of lead author Prof. Hans De Raedt, with such simulations “we can tackle questions that no existing quantum processor can yet solve“.
In sum, Jülich’s 50-qubit simulation is a proof-of-concept that exascale computers can push quantum science forward. It offers researchers a sandbox to experiment with quantum programs at a scale beyond current quantum hardware, helping identify challenges and validate results in advance. The feat also sets the stage for future collaboration between supercomputing and quantum technologies – a trend likely to grow as we approach the limits of classical simulation (simulating 51 qubits would need ~4 petabytes, etc.) and as quantum hardware continues to mature. This achievement not only demonstrates JUPITER’s extraordinary capabilities but also provides a glimpse of a future where HPC and quantum computing evolve hand-in-hand.
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