As a partner at BDO Digital, Walter focuses on innovation with enabling and emerging technologies. Quantum technologies, particularly in computing and sensing, hold the greatest interest, particularly within the Transport and Logistics Industry sector.
That work has taken him from raising awareness inside BDO to developing a quantum optimisation project, together with Mark Thienpont from delaware, for a rail transport routing optimisation after an accident. He also raises market awareness through research and making connections through Quantum Circle.
From optimisation node-edge networks in transport and logistics context to investment and industry adoption, Walter sees experimentation as an essential part of building Belgium’s capabilities in quantum technology.
Where did your interest in quantum computing begin?
It goes back quite a long way.
At university, I came across combinatorial problems that were theoretically solvable but practically took too long to solve with the then-available computing power.
In the context of BDO’s VISION 2030 projects @ Living and Working Tomorrow at the innovation campus in Vilvoorde, the idea of starting a track, “Computing of the Future,” took concrete shape. A panel discussion with a range of market players, including Jan Sonck from Quantum Circle, was the start.
What does your role at BDO Digital involve today?
I focus on innovations with and for service and market development. My whole career has been in technology exploration; hands-on, building use cases to learn to master the technologies, discover the ecosystem, and foster partnerships with vendors and early clients. Quantum technologies and the latest generation of GenAI are currently important areas of focus.
It is a fairly unique position because I spend time looking at technologies that may not yet be part of most colleagues’ daily work.
A large part of my role is also about awareness. People in our organisation and our clients are understandably focused on the work in front of them today. I combine that focus with exploring what is emerging, bringing people into the subject and identifying where there may be opportunities.
That also means building an ecosystem outside BDO. You need like-minded counterparts in organisations, technology providers, and people who are willing to experiment.
You have worked on a quantum optimisation project for rail transport. How did that start?
Through our client relationship with Lineas, the private rail freight operator in Belgium with whom we have had a solid relationship since 2018, with Mark Thienpont from delaware, and Quantum Circle’s ambition to realise a showcase with current quantum thinking and ultimate processing, we started teaming up. We wanted to use an actual operational problem rather than create a purely theoretical exercise.
The case focused on what happens after a disruption.
If a railway station or line suddenly becomes unavailable, passenger and freight trains preferably need alternative routes and transport schedules rather than cancellations. So our objective was to find computationally viable ways to reroute them, delay them, adjust schedules or make other operational decisions. Once several combinations of stations, terminals and routings are considered, but also the resources and assets involved, the number of possible combinations grows exponentially and extremely quickly.
That makes it a very, very interesting optimisation problem.
How did you approach the case?
Together with Mark Thienpont from delaware, who is a PhD student at the University of Maastricht, we worked with Lineas to obtain and prepare the data, formulate the optimisation problem and started building the model.
We collected publicly available rail routing data from Infrabel and passenger train schedules from NMBS. This came with the advice and coaching of Lineas’ CIO Daniel Lievens and railway operations and data specialist Tom Thijs.
We selected a specific disruption location and moment, namely an interruption of the railway connection between Zeebrugge and Ghent. This was on January 13, 2026, at 10 AM. We were sure that only freight trains from Lineas were active on the section of the rail network of interest to us.
The brute-force option was evaluated with 27 affected trains in 11 possible combinations. That created an enormous number of combinations. 27 to the power of 11. An alternative modelling technique based on decomposition of the possible total solution, followed by the simultaneous or parallel optimisation of all sub-solutions was the final solution. You could call this a quantum-inspired solution approach. This way, the calculation was possible within a minute on a classic computer.
Afterwards, the model also ran through a cloud quantum provider to estimate the possible stretch of the approach on denser node-edge networks.
For me, that is the interesting part. You start with an operational problem that people in the railway sector recognise and then you explore (and prove) whether quantum thinking and quantum technology can offer another viable approach.
What happens after a project like that?
We take the results outside. We make people aware to prepare. Prepared to decide.
We are now using the project to show other organisations what quantum optimisation can potentially offer. Transport in general is an obvious domain with well-known problems such as the Travelling Salesman Problem (TSP) and the Vehicle Routing Problem (VRP), but logistics cases involving Resource and Asset Scheduling are also highly relevant.
We have been invited to present the work at a NATO Science and Technology Organisation’s conference in Sweden and the Quantum World Festival event in Cannes. We also participate in 1-to-1 meetings and Roundtables in Belgium and beyond.
That type of exposure is useful because a model becomes much more interesting when other people can challenge it, test the assumptions and consider whether a similar approach could work for their own problems.
Is experimentation important for quantum adoption?
Very much so.
You can attend presentations and read about quantum computing for years. At some point, you need to grasp the modelling techniques and software, as well as the handling of hardware technology. Do not forget the interpretation of the output, as quantum output is probabilistic.
That does not mean every experiment will become a commercial project. The point is to understand what is possible, what the limitations are and what kind of problems are suitable.
For companies, that experience is important. You learn much more by building a model around your own data than by only hearing what someone else has done.
What brought you to Quantum Circle?
There were two reasons.
The first one was learning. Quantum computing covers many areas, and nobody knows everything. Quantum Circle gives me access to people who have knowledge I do not have.
The second one was contributing.
Transport and logistics are areas where BDO and I have experience and where I believe quantum computing solutions are interesting today. If we can bring that expertise into the community while increasing awareness and learning from people working in cryptography, data and data management, GenAI, physics, finance, or other fields, everybody benefits.
I also wanted to explore research initiatives specifically for the Belgian market and identify where we could start building something together.
How has Quantum Circle developed since you joined?
It was a logical evolution. In recent years, Quantum has become better understood by a broader audience, primarily the business audience. There is now more attention for business applications.
In the beginning, much of the focus naturally went to the technology itself. That is important because at first, people need to understand what quantum physics and quantum computing are.
Over time, there has been more interest in what organisations can actually do with it, both today and in the near and distant future, with the further development of quantum technologies. Yes, there is more than one technology, but that falls beyond the scope of this interview.
We are participating in more events, joining panels and taking part in international conferences. There is also more emphasis on experimentation and connecting people who want to work on specific projects.
For me, that is an important development. Technology becomes more meaningful when people start applying it to problems they recognise.
What has the network brought you personally?
It connected me with people who share an interest in quantum but approach it from completely different backgrounds.
Those connections lead to opportunities to exchange knowledge, participate in events and work with people you might otherwise never meet.
For example, I’ve shared stages with people from the community and became involved in initiatives that extend beyond my own organisation.
That is one of the strengths of Quantum Circle. People come from different companies and sectors, but there is enough common interest to create useful cooperation.
What should Quantum Circle focus on next?
I see two directions that can reinforce each other.
The first one is broadening the network. Quantum Circle can connect with other communities and industries where quantum technology may become relevant. That brings new expertise and new use cases into the group.
The second one is going deeper within specific sectors.
Transport and logistics are a good example. Instead of covering broadly everything quantum might eventually do, you can select a concrete industry problem, gather the relevant people and work on it together.
The difficulty is funding. Many organisations are interested, but interest does not automatically mean someone is willing to finance an experiment.
That is one of the obstacles we need to address.
How do you assess Belgium’s position in quantum technology?
Belgium has strong research capabilities.
We have expertise in physics, electronics and related technologies through universities and research institutions. There is clearly valuable knowledge here.
Where I see more difficulty is in getting that knowledge into business applications.
Belgium has many smaller companies, and/or the R&D activities are not in Belgium. They do not necessarily have access to the needed resources; people and money.
Funding is another issue. Other European countries have larger public programmes or more private capital available for quantum companies. Belgian spin-outs can therefore end up looking abroad when they need to finance further growth.
So the expertise exists, but turning that expertise into more industry activity remains a challenge.
Why is business adoption difficult?
Companies need a reason to invest. They want or need to be able to assess the result from the start onward, or at least in the foreseeable future.
People may find quantum computing fascinating, but fascination does not pay for a project. Someone needs to dedicate people, time, data and budget.
That becomes much easier when there is a specific business problem you can test.
It’s the reason why I like the railway case. We are not starting with the technology and searching for something to attach it to. We have an optimisation problem that exists in railway operations and we explore whether quantum can contribute.
More companies need opportunities to experiment in that way.
What would you ask Quantum Circle members to do within their own organisations?
Become advocates.
If you are part of Quantum Circle, take what you learn back into your organisation. Find a use case. Ask for some time. You might secure a budget for an experiment.
A common problem with emerging technology is that many people have an opinion, but relatively few are willing to commit resources to testing it.
At some point, someone has to start.
Belgium has researchers and technology expertise. What we need more of are organisations willing to use that knowledge and build projects around it.
Where would you like your own quantum work to be in five years?
I would like the optimisation work we are doing today to have a life beyond the original project.
Ideally, the node-edge optimisation model, the approach starting from the synthetic data that can grow in volume and complexity with the help of the latest GenAI technologies, would be used by different companies, developed further by others or referenced in academic work.
There is also value in making these data sets available for research and education. If people can use them to test new algorithms, teach students or develop better models, the work continues to contribute.
For me, that would be a meaningful result: not simply completing one project, but creating something other people can continue to use.
This interview is part of Inside the Circle, our series featuring the people advancing quantum innovation in Belgium. Discover the full series here.
