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Luke Bertels: Wigner Fellow explores molecules through the quantum world

Luke Bertels
Luke Bertels, a Eugene P. Wigner Fellow, is helping determine ways to combine artificial intelligence and quantum computing. Credit: ORNL, U.S. Dept. of Energy

There was little doubt that Luke Bertels was going to become a scientist; it was written in the stars, some might say.

Bertels is one of six in a family of scientists: his mother was a biologist, his father was an agricultural economist, two brothers are biologists, one is a neuroscientist, and now Bertels is a quantum computational scientist. His mother, one of six children herself, was a big influence.

“She laid the path for me and my siblings to follow science,” Bertels said. “She would bring us to her research lab beginning from a young age. This instilled in me a lifelong love of science.”

Bertels, a Eugene P. Wigner Fellow at the Department of Energy’s Oak Ridge National Laboratory, broke the family mold by focusing on the physical sciences. Math, chemistry and physics are his dominant interests.

When it came time to pursue a doctorate, newly equipped with an undergraduate degree in chemistry from the University of Chicago, Bertels enrolled at the University of California–Berkeley and looked toward the stars. Because everything known in the universe is formed from stardust—the fusion reactions that make stars shine spew out molecules that form planets and everything else in the visible universe—Bertels wondered about the chemical processes by which these molecules come into being.

Collaborating with professor Ralf Kaiser at the University of Hawaii to study these processes from Earth, Bertels used experimental data to model the reactions of colliding stellar molecules and what is produced from those collisions.

“My dissertation focused on developing and applying theoretical approaches to studying the electronic structure theory of small molecules to gain insight into chemical reaction paths,” Bertels said. The research helped improve the understanding of silicon-carbide formation in the interstellar medium, as well as benchmarking reactive force fields for hydrogen combustion.

Since joining ORNL in July 2023, Bertels works in the Quantum Computational Science group in the Computational Sciences and Engineering Division under his mentor, group leader Ryan Bennink. For his fellowship, he is helping determine ways to combine artificial intelligence and quantum computing, specifically to develop classical and quantum machine learning methods for using adaptive neural networks to study correlated molecules and chemical systems. 

“In essence, the question is, can we build up the techniques and algorithms to efficiently investigate these strongly correlated systems that then have relevance to big problems?” Bertels said.

Bertels says he really enjoys being at a national lab and especially his group. “It’s very scientifically diverse. We are all interested in quantum computing, but we all come from different domains of science. There [are scientists with backgrounds in] chemistry, materials science, nuclear physics, high energy and low energy physics. It’s very interesting, and I get exposed to a lot of different sciences that I previously had no interaction with. It lets me think about other problems with the same tool set that I use to solve my problems.”

On a larger scale, Bertels research revolves around using quantum computers to study chemistry, to find efficient ways to simulate molecules where electrons are strongly interacting. Classical computing is less impactful here, so a new generation of quantum computers—computers that utilize quantum mechanics to solve problems which are intractable on classical computers—can help solve some of these problems. 

Of particular interest to him are metalloenzymes, biological systems that have metal centers with unpaired electrons that can be used for oxidation reduction chemistry. One of the primary metalloenzymes is the iron molybdenum cofactor, FeMoco, used for nitrogen fixing. Nitrogen fixation, where nitrogen combines with other elements to form compounds such as ammonia, can be used industrially, but it has implications for the planet.

“About 1 to 2%of the world’s global energy usage is to fix nitrogen industrially,” Bertels said. “This has significant energy consequences. So if we can understand the chemistry of these nitrogen-fixing systems, can we design a more energy efficient process? We think quantum computing is a way to go about those simulations. That will allow us to tackle these problems that are out of the reach of classical computing.”

Bertels’ research interests include the development of machine learning approaches to quantum chemistry, simulating chemistry and the structure of molecules as precursors to experiments. As a theorist, he wants to provide the foundation through computational results to use chemistry to solve a specific problem. Some applications include drug discovery, materials and catalysis.

As a theorist, “I joke that I’m a fake chemist because I don’t actually play with chemicals,” he said.

Bertels spent his youth among the cornfields in a small town in central Illinois. His family was big on board games, their competitive nature put to good use with Risk or Monopoly, for example. In high school, he was a track and cross-country runner. He was fortunate, he said, to have very supportive teachers in middle and high school who fostered his interest in science. His eighth-grade math teacher pushed him to join the math team, and that “set me up to be more on the chemistry and physics side than everyone else in my family.”

In college, Bertels took a course in mathematical methods in the physical sciences, acquainting him with a professor who would help him make vital contacts. Professor Jack Cohen “just picked up the phone and set me up with my undergraduate research adviser,” Bertels said. His adviser, professor David Mazziotti, in turn was eager to get Bertels started in a research lab.

After earning is doctorate in theoretical chemistry at UC-Berkeley, Bertels did postdoctoral research at Virginia Tech, working in a quantum chemistry lab under professor Nicholas Mayhall. “That was my first real exposure to the field of quantum computing,” Bertels added. 

And while Blacksburg, Virginia, was a great place to sink his teeth into the quantum realm, the region had little diversity in foods that he could sink his teeth into. Coming from California’s culinary heaven, Bertels had to start cooking elaborate meals for himself. Now cooking and baking is a favorite hobby, and while his repertoire is varied, he is fond of making Italian food and is diving into Indian cuisine.

“I had to fill the void so I learned to cook a lot. My palette is well entertained,” Bertels said. . 

An avid hiker among the trails around eastern Tennessee, Bertels plays basketball with other members of ORNL, is interested in Latin dance and is heavily involved with his church, frequently volunteering to cook at a rescue mission in Knoxville.

Bertels easily reconciles science with his faith. “I think there are questions about who and what we are that science is very good at answering, and I think there are questions about who and what we are that science doesn't really have the answers to,” Bertels said. “Those are the metaphysical questions. I'm interested in both. It helps me be a good scientist, and it helps me explore things. It’s where science doesn’t necessarily have the answers that religion steps in for me.”

So, he continues to look toward the stars … for answers to both the physical and metaphysical questions.

ORNL’s Distinguished Staff Fellowship program aims to cultivate future scientific leaders by providing dedicated mentors, world-leading scientific resources and enriching research opportunities at a national laboratory. Fellowships are awarded to outstanding early-career scientists and engineers who demonstrate success within their academic, professional and technical areas. Fellowships are awarded for fundamental, experimental and computational sciences in a wide range of science areas. Factsheets about our fellows are available here.

UT-Battelle manages ORNL for DOE’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, visit — Lawrence Bernard