Level 1 — Absolute Beginner

A quantum computer is a new kind of computer. It uses very small things called qubits to do math.

Quantum computers are still hard to build. They have only a few qubits today. They can break easily.

So scientists use big normal computers to pretend to be quantum computers. This is called a simulation.

Scientists in Germany used a huge computer called JUPITER. They made a simulation of 50 qubits. This is a new world record!

quantum

very small parts of nature, smaller than atoms

qubit

a tiny piece of data in a quantum computer

computer

a machine that does math and runs programs

simulation

a copy of something made by a computer

record

the best result so far

huge

very, very big

Germany

a country in Europe

scientist

a person who studies how the world works

Level 2 — Elementary

Quantum computers are a new kind of machine that could one day solve problems much faster than today's computers. They work with qubits, tiny pieces of information that follow special rules from quantum physics.

Real quantum computers are still small, and qubits make mistakes quickly. So scientists use very powerful normal computers to copy, or simulate, what a quantum computer would do. This way, they can test ideas before the real hardware is ready.

This week, researchers at the Jülich Supercomputing Centre in Germany announced a new world record. Using JUPITER, Europe's first exascale supercomputer, they fully simulated a universal quantum computer with 50 qubits. The old record was 48 qubits.

The simulation needed about two petabytes of computer memory, which is around two million gigabytes. The team says the new tool will help engineers design better algorithms and check ideas long before real quantum chips can run them.

simulate

to copy something with a computer or model

physics

the science of how matter and energy behave

hardware

the physical parts of a computer or machine

researcher

a person who studies a subject in depth

exascale

able to do at least a billion billion calculations per second

memory

the part of a computer that stores data while it works

petabyte

a unit equal to about one million gigabytes

algorithm

a step-by-step set of rules a computer follows

Level 3 — Intermediate

Researchers in Germany have announced a milestone in computational physics: the first fully detailed simulation of a universal 50-qubit quantum computer. The achievement, presented this week, broke the previous benchmark of 48 qubits and was carried out by a team at the Jülich Supercomputing Centre working with NVIDIA on JUPITER, the first exascale supercomputer in Europe, which went online at Forschungszentrum Jülich last September.

Simulating quantum systems on classical hardware becomes exponentially harder with each added qubit, because the number of complex amplitudes the simulation must track doubles every time. Reaching 50 qubits required roughly two petabytes of memory — about two million gigabytes — a capacity that, according to centre director Kristel Michielsen, is currently available only on the world's largest supercomputers.

To get there, the team rewrote its custom simulation software, the Jülich Universal Quantum Computer Simulator (JUQCS), producing a new version called JUQCS-50. The release exploits the hybrid memory architecture of NVIDIA's GH200 Grace Hopper Superchips, temporarily moving data between GPU and CPU memory with minimal performance loss. That trick effectively turns JUPITER's tightly coupled CPU-GPU layout into a single, very large quantum-simulation workspace.

Why does this matter? Real quantum hardware in 2026 is still error-prone and limited to several hundred noisy qubits at most. A reliable 50-qubit simulator gives algorithm designers a sandbox in which to test programs, error-correction strategies and noise models before committing them to scarce real-machine time. The work, posted to the arXiv preprint server, is expected to be used to benchmark forthcoming European quantum hardware and to support climate, materials-science and pharmaceutical research that already relies on JUPITER for non-quantum workloads.

exponential

growing or shrinking faster and faster as you go

amplitude

a number that describes the strength of a quantum state

classical

relating to ordinary, non-quantum physics or computing

petabyte

a unit equal to about one million gigabytes

GPU

graphics processing unit, a chip good at many parallel calculations

benchmark

a standard against which something is compared or tested

preprint

a scientific paper shared online before formal peer review

sandbox

a safe testing area for new ideas or programs

Level 4 — Advanced

A collaboration between Forschungszentrum Jülich and NVIDIA has reported the first fully entangled simulation of a universal 50-qubit quantum computer, edging past the long-standing 48-qubit ceiling and giving algorithm designers a credible classical sandbox in advance of fault-tolerant quantum hardware. The work was carried out on JUPITER, Europe's inaugural exascale machine, which went into production at Jülich last autumn and is the first system on the continent to clear the exaflop threshold for sustained double-precision performance.

Universal quantum simulation scales exponentially in memory: a system of n qubits requires storage proportional to two-to-the-n complex amplitudes, so each additional qubit doubles the working set. Pushing from 48 to 50 qubits demanded roughly two petabytes of fast memory and a software rewrite tuned to the heterogeneous GH200 Grace Hopper Superchips that anchor JUPITER's node design. The result, dubbed JUQCS-50, exploits NVLink-C2C bandwidth between GPU and CPU memory pools to spill state vectors in coordinated chunks with what the team reports as 'minimal performance degradation.'

Operationally, the breakthrough matters less because it surpasses a numerical record and more because it widens the design envelope for near-term quantum algorithms. Real machines in 2026 remain noisy, with characteristic error rates that limit useful circuit depth, and the most ambitious experiments still struggle to certify entanglement across the full register. A reliable 50-qubit classical reference lets researchers explore error-correction codes, variational ansätze and hybrid quantum-classical workflows in a setting where every amplitude is known, providing ground truth against which actual hardware can be benchmarked.

Beyond quantum work, the achievement strengthens Europe's broader high-performance-computing posture. JUPITER's portfolio already spans climate modelling, neuroscience and pharmacological simulations, and the JUQCS-50 release is intended to be made available to qualified academic and industrial users, including teams at IQM, Pasqal and Quantinuum that are building competing quantum platforms. As the boundary between classical and quantum advantage continues to shift, the ability to run a faithful 50-qubit emulation on European hardware reduces strategic dependence on US- and China-based simulation services and gives the continent a concrete stake in shaping the protocols on which the next decade of quantum computing will be built.

entanglement

a quantum link in which the state of one particle depends on another, even at a distance

fault-tolerant

able to keep working correctly even when errors occur

double-precision

a computer number format that uses 64 bits for high accuracy

heterogeneous

made up of different kinds of parts working together

state vector

the mathematical object that fully describes a quantum system