A new Qiskit function that integrates real-world constraints natively into the quantum computation, producing better and faster solutions to complex optimization problems, executed on IBM quantum hardware.
MUNICH, Germany, September 15, 2026 — Aqarios GmbH today launched the Constrained Quantum Optimizer, a new solution in the IBM Qiskit Functions Catalog that organizations can use to help solve complex, real-world planning and scheduling problems using quantum computing. Built on Aqarios’ FlexQAOA algorithm, it integrates the constraints of an optimization problem natively into the quantum algorithm, producing better, valid solutions that penalty-based approaches can’t guarantee.
Constrained Quantum Optimizer
Behind many of an organization’s most consequential planning decisions lies an optimization problem: finding the best possible option from countless alternatives while satisfying a set of hard constraints. Businesses use it to cut costs, reduce travel time, allocate scarce resources, and improve efficiency. As these problems grow in size and complexity, classical methods become increasingly time consuming, making them ideal candidates for quantum approaches that can reach solutions beyond what classical methods can deliver today.
Industries from logistics and manufacturing to telecommunications and energy solve problems like these every day. As organizations in these industries explore quantum computing, optimization functions like the Constrained Quantum Optimizer, in the IBM Qiskit Functions Catalog can be a starting point for putting it to work on real optimization problems.
“Optimization is one of the most compelling categories of problems for the development of quantum advantage-capable applications. Now, through our Qiskit Functions Catalog, users can experiment with Aqarios’ Constrained Quantum Optimizer to push this boundary — and explore trusted results for constrained combinatorial optimization problems,” said Scott Crowder, Vice President, IBM Quantum Adoption and Business Development.
Solving a constrained problem conventionally means folding its constraints into the objective function as penalty terms, a manual reformulation repeated for every new problem. This makes the problem harder to solve and no longer guarantees that the constraints are actually satisfied. Yet those constraints are always essential.
The Constrained Quantum Optimizer works differently. It keeps a problem’s constraints intact and embeds them directly into the quantum circuit, ensuring that only valid solutions are ever considered. Take a delivery operation where every order must be loaded onto exactly one vehicle: never zero, never two. That kind of rule, called a one-hot constraint, is easy to state but just as easy for a solver to break. The Constrained Quantum Optimizer enforces it by design, so the computation never explores invalid solutions, uses the quantum hardware more effectively, and returns higher-quality results. Other kinds of constraints are handled automatically as well, with no extra work from the user. Businesses can describe their optimization problem in the standard formats their planning and operations teams already use, and the function takes care of everything else.
To validate the approach on real hardware, Aqarios ran the function on an IBM Quantum Heron processor, on a 144-bit problem with 48 one-hot constraints. Across five test instances it reached optimal or near-optimal solutions every time, finding the exact optimum in three and landing within about one percent in the other two.
“Most quantum optimization tools still make you work around your constraints. We build them in natively, and that’s what turns quantum computing into real, usable results for constrained problems,” said Michael Lachner, CEO, Aqarios. “We’re glad to bring what already runs on our Luna platform directly to IBM Quantum users, via the Qiskit Functions Catalog.”
The Constrained Quantum Optimizer builds on FlexQAOA, which already powers constrained optimization for paying customers on Aqarios’ Luna platform. On that proven foundation, Aqarios combines the algorithm with approaches designed specifically for IBM quantum hardware, bringing it to the Qiskit Functions Catalog for developers, researchers, and businesses to use directly.
The Constrained Quantum Optimizer is available now for IBM Quantum users through the IBM Qiskit Functions Catalog.
About Aqarios
Aqarios, headquartered in Munich, Germany, and a spin-off of LMU Munich, is a provider of quantum computing software for optimization across industries including energy, aerospace, logistics, finance, and manufacturing. Aqarios delivers practical, hardware-agnostic tools, including its Luna platform, which lets organizations run optimization across classical, hybrid, and quantum backends through one interface. It has collaborated with globally recognized organizations to put quantum optimization to work. Aqarios GmbH is a subsidiary of Aqarios Quantum Technologies AG, listed on the Düsseldorf Stock Exchange since 2026.
