Yet the promise of quantum computing is still limited by today’s hardware. Current devices operate in the so-called NISQ era (Noisy Intermediate-Scale Quantum), where qubits are scarce, error-prone, and difficult to control. To make quantum computing useful, researchers must find ways to overcome these limitations. That is where quantum software plays a critical role.

Why Quantum Software Matters?

Quantum algorithms are often described at a high level, but to run them on hardware, they must be compiled into quantum circuits. These circuits specify the exact operations performed on qubits. However, the translation from algorithms to circuit is rarely efficient: the resulting circuits are often far larger and noisier than necessary. Each extra operation increases noise and reduces reliability.

Quantum circuit optimization – finding smaller, faster, and less noisy equivalents of a given circuit – is therefore one of the key challenges for enabling near-term real-world quantum applications. Optimized circuits not only increase accuracy on today’s noisy machines but also reduce the costly overhead of quantum error correction, which is needed for future fault-tolerant quantum computers.

Quantum Software at the Department

At the department, the new Quantum Software Team, led by Professor Jaco van de Pol, is tackling this challenge head-on. The team combines expertise in formal methods, automated verification, and high-performance algorithms with the demands of quantum computing, aiming to push the boundaries of what is possible in quantum software.

As Professor van de Pol explains: “We want to make quantum computing practical by bridging the gap between algorithms and hardware. By optimizing quantum circuits, we reduce noise, save resources, and ultimately enable applications that would otherwise remain out of reach.”

The Quest for Optimal Quantum Circuits (QoptiQ) project, funded by the Danish e-infrastructure Consortium (DeiC), focuses on developing algorithms that go beyond the rough shortcuts used in today’s quantum compilers, instead aiming for circuits that are mathematically proven to be optimal - from reducing gate counts and circuit depth to handling hardware-specific connectivity constraints.

Another project, joint with Department of Physics and Astronomy, Aarhus University, funded by the Novo Nordisk Foundation Quantum Computing Programme (NQCP), will explore efficient implementations of quantum error correction codes, an essential step toward scaling quantum computing from today’s noisy devices to fully fault-tolerant quantum computers.

Other topics of interest include the design of practical, high-level quantum programming languages, compiler techniques, and tools for automated synthesis, verification, and simulation of quantum programs. Together, these initiatives support a long-term vision of building a quantum software stack that bridges the gap between high-level algorithms and low-level circuits, enabling practical applications ranging from drug discovery to logistics and finance.

Strong Partnerships 

The department works closely with Kvantify, a Danish quantum start-up, where the industrial postdoc Irfansha Shaik, funded by Innovation Fund Denmark, is shared between the department and the company. Together, they published cutting-edge research on quantum layout synthesis and circuit optimization, enabling Kvantify to simulate enzymatic reactions on a quantum computer with chemical accuracy[SR1] .

The department is also engaged with Quantum Campus Aarhus, the Danish e-infrastructure Consortium (DeiC), and forms the Quantum Software Satellite of the Novo Nordisk Foundation Quantum Computing Programme (NQCP), ensuring that its efforts are tightly integrated into national and international networks. 

Looking Ahead

Quantum computing is widely recognized as a major frontier in research, with the potential for enormous societal and economic impact. With new projects, strong collaborations, and fresh talent joining the field, the department is contributing to Denmark’s growing capacity in quantum technologies.

For more information reach out to Professor Jaco van de Pol and follow their work on cs.au.dk/QS.