Designing Tomorrow’s Molecules with Quantum Computers

University of Sydney Young Scientist Christophe Valahu is looking forward to this year’s 75^th Lindau Nobel Laureate Meeting where he will join three physics Laureates – Michel H. Devoret, John M. Martinis and William D. Phillips – in a panel discussion on the future impact of quantum computing (2 July 2026, 9:00 CEST).

Christophe Valahu will bring to the discussion his experience as a quantum physicist developing quantum computers into powerful, new tools which, it is hoped, chemists will be able to use to design new molecules that are shaped for specific tasks. Among the many breakthroughs the work could lead to are new drugs, more efficient solar cells, better sunscreens and other innovative new materials.

From Trapped Ions to Molecular Simulations

At the heart of Christophe’s work is his expertise in operating trapped ion quantum computers, which involves manipulating individual atoms inside small vacuum chambers in the lab where he works at the University of Sydney’s Nanoscience Hub.

His current experiment traps a single ionized atom of ytterbium, a rare earth metal, inside a chamber about the size of a couple of coffee cups. Using electric fields, the ion is positioned so precisely that he can aim lasers directly at it and deliver precisely calibrated jolts of energy. He creates a qubit – the building block of a quantum computer – from a pair of the ion’s electronic energy levels.

But the quantum information is not only residing in the qubit. It’s also held in the vibrational modes of the ion. Using laser stimulation, he can also play with the vibrations, storing additional quantum information. Put together with the information in the qubit, there is enough to simulate a simple molecule.

The technique promises to be more efficient than other quantum computers which need to use multiple qubits to get similar results. “Using the vibrations and the electronic levels, we’re able to very efficiently simulate these kinds of problems because we’re using all the information that’s available to us,” Valahu says.

He sees his current single ion experiment as demonstrating proof of concept for the future. “Then it’s about scaling … Hopefully we can add more ions and retain the advantages we had with a single one.” And with each additional ion which can be successfully added without losing control of the system, the computer will be able to simulate molecules that are more complex.

But why use a quantum computer to figure out the chemical properties of a hypothetical molecule? The answer is that a quantum computer, which operates natively in the quantum world, can do extremely quickly what even a cluster of supercomputers would struggle with.

The quantum computing communities’ goal, Christophe Valahu says, is to get to a place where a quantum computer will be able to do, in a matter of minutes or hours, chemistry simulations which would take a year or even ten years using a supercomputer cluster. But there is still some distance to go. “What those simulations actually look like, what kind of molecules we’d be simulating, that’s still an open question,” he says.

Looking Beyond Physics

Christophe Valahu welcomes the interdisciplinary theme of this year’s Nobel Laureate Meeting. His own research, by its nature, cuts across disciplinary boundaries and he will have the opportunity to meet both physicists and chemists as well as discuss broader scientific issues at the meeting. “One thing I really look forward to is hearing people that have a wealth of knowledge and experience, hearing their thoughts on the role of science nowadays.” He would also like to hear Laureates’ views on “how to navigate science, what it means to be a good scientist and what it means to be a good researcher”.

“I’m quite looking forward to hearing about different people’s experiences. And on a more personal level I’m interested to learn about what motivates other people, what kept them going and what excites them.”
Christophe Valahu is one of nine Australian Young Scientists attending the 75^th Nobel Laureate Meeting. The nine are all either doctoral candidates or post-doctoral researchers, and their participation is supported through Australia’s Science and Industry Endowment Fund (SIEF) and administered by the Australian Academy of Science.

The Other Eight Delegates

• Shankar Dutt of the Australian National University, who is developing tiny sensors to detect disease at its earliest stages.
• Anna Faber of the University of Western Australia, who is engineering marine bacteria to break down plastic and create biodegradable alternatives.
• Caitlin Gare of the Australian National University, who is developing peptides and RNA as promising chemical tools and novel therapeutics.
• Lottie Morison of Murdoch Children’s Research Institute, a speech pathologist studying communication impairments in children and young people.
• Astrid Stubbusch of Monash University, who is investigating how microorganisms’ use of different energy sources shapes their distribution and responses to environmental changes.
• Mike Tebyetekerwa of the University of Queensland, who is designing electrochemical generators to produce green chemicals and capture carbon dioxide.
• Thomas Williams of the University of Melbourne, who is developing new mathematical models to study how bacterial membranes develop and function.
• Belinda Zhangof the University of Sydney, who is using peptide synthesis and molecular biology techniques to discover drug molecules that are more stable and longer lasting in the body.