Ingmar Swart appointed Professor of Experimental Quantum Materials

Ingmar Swart appointed Professor of Experimental Quantum Materials

Unraveling the quantum world atom by atom

On April 1st, 2024, Ingmar Swart was officially appointed as Professor of Experimental Quantum Materials at Utrecht University. In his lab, he constructs materials atom by atom and investigates the electronic properties of these structures. "What primarily drives me is the possibility of being the first one in history to discover how something works."

Ingmar Swart's workspace in the Ornstein Laboratory reflects his background in fundamental natural sciences. He points to a painting on the wall. "This is a painting depicting the Doppler effect. The physicist Buys Ballot conducted research on this phenomenon in Utrecht. At that time, the research had no practical application, but nowadays, the Doppler effect is used in various applications such as radar imaging and ultrasounds." According to Swart, this demonstrates that fundamental research sometimes pays off only much later. "You can never predict the future applications of such discoveries."

There's something else notable in the room. Beyond the painting, in the back of the room, is a walker. "Hopefully, that will be gone soon, but I had a severe bicycle accident two years ago, which resulted in a spinal cord injury," Swart explains. "Suddenly, I encountered all sorts of obstacles I didn't know existed. So, to start working as a professor almost two years later, is extra special."

With a scanning-tunneling microscope, researchers can move atoms as if sliding them alongside each other

Building atom by atom

In his lab, Swart and his team develop quantum materials, then study the properties of these materials at a fundamental level. What's remarkable is that the researchers work on the nanoscale: using a scanning tunneling microscope, they can build materials atom by atom. The microscope operates with a razor-sharp needle, allowing atoms to be moved as if sliding them alongside each other. "For example, you can slide a row of four atoms next to each other and study the properties of this row. How strong is it? Does it conduct electricity well or not? But you can also investigate what changes when you slide in one extra atom, remove one, or alter the entire shape."

Flocks of electrons

Swart is particularly interested in the electronic properties of these atomic arrangements. He studies where electrons are located and how they move within a material. "In physics, we don't yet fully understand how multiple electrons interact with each other. Existing knowledge about electrons is often based on theories and measurements of single electrons. That's why we understand, for example, why this table doesn't conduct electricity, while this copper cup does."

He compares groups of electrons with flocks of starlings. "Starlings in a flock all move together. When you study such a flock, you can examine its properties, such as density, colour, and shape, and how they change. These properties are determined by the way starlings react to each other. But if you take a single starling out of that mass, you can't say anything about the properties of the flock." Just like you can't deduce the properties of a flock of starlings by studying one bird, you can't understand the interactions between electrons by analysing just one electron.

I think curiosity-driven research is a quintessential task for a university. If it doesn't happen at the university, it won't happen anywhere.

Superconductivity

Often, interactions between electrons underpin quantum mechanical phenomena, such as superconductivity. While much is known about superconductivity at extremely low temperatures, superconductivity at higher temperatures remains largely unexplained. Such phenomena fascinate Swart. "I want to know precisely how the world works at the scale of molecules and atoms. Which phenomena from quantum mechanics can we utilise? And what effects do those phenomena have on a larger scale?" Just like with Buys Ballot's findings, you never know what that knowledge will eventually be useful for. "I think curiosity-driven research is a quintessential task for a university. If it doesn't happen at the university, it won't happen anywhere."

Murals

In addition to his scientific work, Swart is one of the driving forces behind a series of murals depicting discoveries by Utrecht scientists. "The university has a rich history, particularly in the natural sciences. But how many people in Utrecht are aware of these discoveries and their significance? To strengthen the bond between the university and the city, and more generally between society and science, we've created a number of murals. I'm collaborating on this with a former colleague, Sander Kempkes, and the artists from De Strakke Hand. It's especially enjoyable to collaborate with people from other disciplines. There are many more discoveries deserving of murals, so we hope to expand the series in the coming years."

De Strakke Hand created a mural depicting the dopplereffect

About Ingmar

Swart has been associated with the Debye Institute for most of his academic career. After completing his Bachelor's degree at Utrecht University, he only left the Institute for a research project at Berkeley in 2004 and for his Rubicon fellowship at the University of Regensburg between 2009 and 2012. In his new role, Swart will work for both the Chemistry and Physics departments and will collaborate closely with theorists in the field of quantum materials.