For the first time, researchers at the University of Sydney have used a quantum computer to directly watch and engineer a process that is crucial in chemical reactions by slowing it down by a factor of 100 billion.
Joint lead researcher and PhD student, Vanessa Olaya Agudelo, said: “It is by understanding these basic processes inside and between molecules that we can open up a new world of possibilities in materials science, drug design, or solar energy harvesting.”
“It could also help improve other processes that rely on molecules interacting with light, such as how smog is created or how the ozone layer is damaged.”
The research team specifically observed the interference pattern of a single atom induced by a ‘conical intersection,’ a typical geometric shape in chemistry.
Conical intersections are well-known in chemistry and are essential to quick photochemical reactions like photosynthesis and light harvesting for human vision.
Since the 1950s, chemists have attempted to directly witness these geometric processes in chemical dynamics, but due to the incredibly quick timescales involved, this is not possible.
The School of Physics and the School of Chemistry developed an experiment using a trapped-ion quantum computer in a novel manner to circumvent this issue. This allowed them to design and map this very complicated problem onto a relatively small quantum device – and then slow the process down by a factor of 100 billion.
This is a fantastic collaboration between chemistry theorists and experimental quantum physicists. We are using a new approach in physics to tackle a long-standing problem in chemistry.
Dr. Ting Rei Tan
Their research findings are published today in Nature Chemistry.
“In nature, the whole process is over within femtoseconds,” said Ms Olaya Agudelo from the School of Chemistry. “That’s a billionth of a millionth or one quadrillionth of a second.”
“Using our quantum computer, we built a system that allowed us to slow down the chemical dynamics from femtoseconds to milliseconds. This allowed us to make meaningful observations and measurements.”
“This has never been done before.”
Joint lead author Dr. Christophe Valahu from the School of Physics said: “Until now, we have been unable to directly observe the dynamics of ‘geometric phase’; it happens too fast to probe experimentally.”
“Using quantum technologies, we have addressed this problem.”
Dr. Valahu said it is akin to simulating the air patterns around a plane wing in a wind tunnel.
“Our experiment wasn’t a digital approximation of the process this was a direct analogue observation of the quantum dynamics unfolding at a speed we could observe,” he said.
Molecules transfer energy at breakneck speed in photo-chemical reactions like photosynthesis, through which plants obtain their energy from the Sun. These places of exchange are known as conical intersections.
This research slowed down the dynamics of the quantum computer and exposed the telltale signs associated with conical crossings in photochemistry that were predicted but never observed before.
Co-author and research team leader, Associate Professor Ivan Kassal from the School of Chemistry and the University of Sydney Nano Institute, said: “This exciting result will help us better understand ultrafast dynamics how molecules change at the fastest timescales. It is tremendous that at the University of Sydney we have access to the country’s best programmable quantum computer to conduct these experiments.”
The quantum computer used to conduct the experiment is in the Quantum Control Laboratory of Professor Michael Biercuk, the founder of quantum startup, Q-CTRL. The experimental effort was led by Dr. Ting Rei Tan.
Dr. Tan, a co-author of the study, said: “This is a fantastic collaboration between chemistry theorists and experimental quantum physicists. We are using a new approach in physics to tackle a long-standing problem in chemistry.”
