Journeys of Discovery: Nuno Araújo, the physicist who sees order in turbulence

Nuno Araújo is today recognised as a prominent figure in Physics in Portugal, but his path does not follow a straight line: it is shaped by unlikely shifts, decisive encounters and an intellectual curiosity that never settles. “I never had a rigid plan,” he admits. “What I always had was the desire to learn new things and to challenge myself.”

There is a constant sense of enthusiasm in the way Nuno Araújo speaks about his work - as if he were still, even today, almost surprised by the ways in which physical reality organises itself. If there is a recurring image in his discourse, it is this: the movement of many things at once which, taken together, reveals an invisible structure. It is like this with particles, with molecules, with cells, with shoals of fish, and - as becomes clear when speaking with him - with scientific careers themselves.

A Full Professor and Head of the Department of Physics at the Faculty of Sciences of the University of Lisbon (Ciências ULisboa), a member of the Centre for Theoretical and Computational Physics (CFTC) and Vice‑President of the Data Science Portuguese Association (DSPA), Araújo has become a central figure in global research in soft condensed matter and statistical physics.

Unlike the romantic narratives some scientists evoke, his path did not begin with a revelatory moment. “There was never a decisive moment in which I had a revelation,” he says. Choosing Physics was “natural”, almost inevitable, although he explored parallel paths — such as Biology and Chemistry — before entering higher education. In secondary school, he joined the Youth Science Association and soon realised that what attracted him was both science and education.

He studied Physics at the University of Minho, where he completed his PhD in 2009 in the same field. This was followed by an international trajectory — five years of postdoctoral research at the Swiss Federal Institute of Technology (ETH Zurich) — which shaped his view of research and the role of institutions. His return to Portugal came in 2014, for personal reasons and also through his encounter with Professor Margarida Telo da Gama, an international reference in the field.

“When I arrived, I was lucky to find what I considered to be an oasis at the CFTC of the Faculty of Sciences,” he says. “There were computers that rivalled the best in Europe, a world‑class library on condensed matter, and a tradition of strategic investment. The most impressive thing is that the computers had been acquired by researchers who were not yet doing simulations, but already had that vision.”

His research focuses on the emergent properties of systems with many particles. Araújo explains the field with the precision of someone who has refined dozens of analogies: how is it possible that things so simple can, together, display such complex properties?

“When I talk to you about silver, what comes to mind? A solid, a silvery metal. Well, if you take a single silver atom, it is green.” The smile appears. “Condensed matter is this: understanding how a collection of green atoms becomes a silvery metal.”

Later, he elaborates: “To describe a drop of water, you would have to solve an inconceivable number of equations. Just to store the initial positions of the molecules, you would need 10,000 times Google’s memory, and to calculate their movement over a thousandth of a second you would need the best supercomputer in the world working for the age of the universe. So, we have to be intelligent: find simple models that capture the relevant physics.”

It is not only the difficulty that attracts him - it is the fact that there is no unifying theory capable of explaining all these behaviours. Each system demands creativity, new combinations, approaches that bring together mechanics, electromagnetism and fluid dynamics. “That is the challenge of condensed physics, and that is what sets it apart.”

Perhaps that is why he feels comfortable working in the hybrid zone between different scientific fields, such as physics and biology. In living systems, he says, the particles “are active: they can grow, divide, swim”. These are systems that introduce autonomy and chaos - and that require new conceptual tools. In them, he seeks “universality”, common properties that make it possible to describe very different phenomena: from cells to shoals of fish.

The international and interdisciplinary dimension of his work becomes particularly visible with the RODIN project, recently funded with ten million euros by the European Research Council (ERC). This project aims to create dynamic biomaterials that can be manipulated by living cells. It is a collective effort linking the Universidade de Aveiro, Imperial College London and the CFTC, bringing together biology, materials, theoretical modelling and artificial intelligence.

Nuno Araújo is also, for many of his students, a kind of intellectual compass - a role that inevitably appears in the stories of those who have worked with him. André Nunes, now responsible for artificial intelligence solutions at the paper company Renova, was Araújo’s first PhD student. When he speaks of his former supervisor, two words always come up: rigour and availability.

“He is one of those people to whom you can hand a scientific paper and the next day you already have comments,” he says. “He gives feedback very quickly. There is very close supervision. He offers constructive criticism. He gives a lot of himself.”

Nunes met him during a lecture while he was a Master’s student at Ciências ULisboa, even before Araújo had returned permanently from Switzerland. He asked the researcher to supervise his thesis, and their collaboration produced strong results, even during the Master’s. “We worked very well together. We published a paper straight away. That weighed heavily in my decision to stay in Portugal for the PhD,” he recalls.

One of the most memorable episodes André recounts illustrates the intellectual environment Araújo seeks to create: for André’s PhD defence jury in March 2020, he invited two prestigious German professors. On the eve of the defence, they asked whether they should adopt a more relaxed or more assertive questioning style. Araújo replied: “go as hard as you can”.

The result was a defence focused less on the thesis itself and more on the ability to think, respond to new situations and reason under intellectual pressure. The first question, on how to simulate the COVID‑19 virus computationally, anticipated the global collapse that would follow: one day later, airports closed. André completed his PhD with honours.

The episode reveals not only academic rigour, but also Araújo’s confidence in his students and in the training he provides. “He continues to follow my path,” says André Nunes. “He even recommended me for professional positions. The job I have today came from a contact he made.” The story sums up more than a supervisory style: it describes a way of being in academia that contrasts with the distant, hierarchical caricature often associated with the university world.

He often recalls that it is not the lack of resources that limits Portuguese science — but pessimism. “The greatest challenge is fighting negativity. The problem is not funding. All countries have problems. The difference lies in people’s motivation. We must motivate through the frontier of knowledge.”

There is an idea to which Araújo frequently returns: science as a method of reasoning, rather than a collection of results. Enumerating hypotheses, testing them, validating with data, structuring thought - this is what he considers essential to pass on to new generations of students. “That way of thinking becomes ingrained in a scientist and allows them to make decisions in many places that are often not a laboratory.”

Perhaps that is why he enjoys teaching so much. “I like asking them questions,” he confesses. In a recent class, he asked what a fluid was - and the discussion lasted several minutes. “It is important to get them talking about things they work with every day, but have never really thought about.”

That is also why he fears a future in which technological urgency outweighs understanding. “The need for an immediate solution is pulling strongly towards answers and less towards comprehension. That is my greatest fear: thinking that knowledge is no longer necessary.”

As Vice‑President of the DSPA, he follows closely the evolution of data science and artificial intelligence. He has no illusions: it is a profound transformation, even if it is not a miracle. For him, we are already at the stage where we begin to understand the limitations of the models - and, more importantly, to learn how to integrate them usefully.

In an episode he likes to tell, which took place at ETH before his return to Portugal, he noticed an elderly man having lunch alone at a table slightly apart from the others in the Chemistry department canteen. He was a Nobel Prize laureate in Chemistry. No one seemed to notice. “There he was just one among many,” he recalls. In Portugal, he imagines, the presence of a Nobel laureate would attract a small crowd.

The story reveals something profound about the way he sees the scientific world: great names and great discoveries matter. Yet they only make sense within the collective continuum of research — in the sandpile where each grain can trigger an avalanche, but where no grain exists on its own.

Perhaps that is why he rejects the idea of a single great scientific question he would like to see answered. “I wouldn’t want all problems to be solved, otherwise I’d lose my job,” he says, amused. But he immediately adds, in a serious tone: “What I want is for the next generations to continue believing that this is the way to develop knowledge.”

Journeys of Discovery is a new feature showcasing researchers from the Faculty of Sciences of the University of Lisbon whose work has been distinguished with European Research Council (ERC) grants. Beyond the projects and scientific results, it aims to explore the paths, ideas and ways of thinking that shape excellence in research. Over the coming months, we will delve not only into what they investigate, but how they arrived there - the choices, the challenges and the vision that guides their work.