Stefano Polla joins the Amsterdam quantum community after his education in Milan (Italy) and Leiden, during which he has demonstrated his excellence and scientific independence in the field of quantum computing. He has won prizes with his Master’s research, and his PhD thesis was nominated for the 2024 award for best PhD thesis at the Leiden Faculty of Science. It describes new quantum algorithms, targeting some of the key challenges in the simulation of complex quantum systems.

Polla is quite happy with his new position: “Amsterdam is a great place to do research in quantum computing. UvA is among the first academic institutions devoting their attention to this relatively young field of research – QuSoft already celebrated their 10-year anniversary. The connection with QuSoft and the broader Dutch quantum software community allows me to integrate the latest theoretical advancements into my research.”

Quantum chemistry

In his research, Polla develops methods and applications of quantum computing for chemistry. “Chemistry is a fascinating field for the application of quantum computing, as molecules are quantum systems by their very nature. Only two years after quantum theory was first conceived, Born and Oppenheimer introduced a way to use it for describing molecular systems. Since then, scientists use this approach to simulate molecules and their behaviour."

"A century ago, all they had was pen and paper. A lot of progress has been made since, but even sophisticated models running on today’s most powerful computers still fail in describing some systems. We expect quantum computing to significantly alleviate these limitations.”

Alas, no suitable quantum computers are yet available for this purpose. Current systems suffer from noise issues and have only a small number of qubits. They can handle some very basic problems, but are far too limited for performing quantum chemical calculations. “Of course”, says Polla, “since huge efforts are being made to improve quantum computing hardware, at some point this will change. In our research, we prepare for that moment, and try to make it happen sooner.”

New drug molecules, new materials

In the absence of a reliable quantum computer, Polla explains, developing quantum algorithms relies on the clever use of mathematical methods and models running on classical computers. At the same time, an important part of the work is to reduce the complexity of quantum chemical problems so that they can be modelled on early quantum computers. Companies like IBM, Google, and Microsoft, as well as startups and scale-ups all over the world are already working on this. They are motivated by the search for new drug molecules and the development of new materials, for instance for batteries or solar cells.

Polla is in close contact with developers in this community. He contributes, among other things, by developing a method to increase the value of the noisy data produced by rudimentary quantum computers. “The concept is to apply machine learning, powered by classical computers, to combine the noisy data from early quantum computers with the power of advanced classical approaches. This might not only improve the data quality, but also help us to learn more about complex quantum systems, and about the quantum computer itself.”

High-risk, high-reward

Finally, Polla also wants to explore other computational problems in the chemistry domain, other than molecular modelling, where quantum computing might be of use. He thinks of complex data processing in analytical chemistry, for instance in the sampling of the so-called chemical space, the realm of all possible stable, small-molecule compounds. “I think that academic research is especially well-suited to explore new computational problems”, he says. “Connecting researchers in chemistry, computational modelling, and quantum technology, we will embark on a high-risk, high-reward exploration of the possibilities. We might encounter many apparent failures, but we will also contribute significant improvements, and pave the road to relevant applications.”

About Stefano Polla

Stefano Polla (1994) obtained his BSc at the University of Milan in 2016 with the distinction ‘Cum Laude’ on a project combining experimental quantum optics and quantum information theory. He then moved to Leiden University where he followed the Casimir Master track in physics, focusing among other things on quantum optics and spin qubits. In his MSc thesis on Quantum Digital Cooling he presented a method to prepare complex low-energy states by only resetting one qubit at a time. It won him the 2019 Lorentz award from the Royal Holland Society of Sciences and Humanities (KHMW), and the 2019 Casimir prize honouring the best MSc students in (Applied) Physics of Leiden University and TU Delft. He obtained his Master’s degree with a 'Summa Cum Laude' distinction, reflecting his inventiveness and breadth of knowledge.

Polla then started his PhD studies in Leiden in the field of Applied Quantum Algorithms, supervised by Prof. Carlo Beenakker and Dr Tom O’Brien. In his thesis ‘The power of one qubit in quantum simulation algorithms’ he describes new quantum algorithms for the simulation of complex quantum systems. It spans from quantum state preparation to mitigation of hardware and algorithmic noise, and from efficient expectation value measurement to noise-resilient applications in quantum chemistry. Central to his approach to these subjects is the active and distinctive role of a single auxiliary qubit. His thesis was nominated for the C.J. Kok Jury Award 2024 for best PhD thesis at the Leiden Faculty of Science.  His PhD and subsequent work included a collaboration with the Theoretical Chemistry group of Prof. Luuk Visscher at Vrije Universiteit Amsterdam. In the final two years of his doctoral research, he also held a part-time role as a student researcher with the Google Quantum AI team.

See also

Homepage Stefano Polla