Home Science & Technology A quantum device used to slow down a chemical reaction 100 billion times

A quantum device used to slow down a chemical reaction 100 billion times

A quantum device used to slow down a chemical reaction 100 billion times

Quantum chemistry close up art concept

Researchers at the University of Sydney have used a quantum computer to slow down and directly observe a key chemical reaction process, revealing details previously invisible due to its fast time frame. This breakthrough offers new insights into materials science, drug design, and more.

What happens in femtoseconds in nature can now be observed in the laboratory in milliseconds.

Scientists from University of Sydney achieved a groundbreaking feat by directly observing a critical chemical reaction process, using a quantum computer to slow it down 100 billion times.

Joint Principal Investigator and PhD student Vanessa Olaya Agudelo said: “It is by understanding these fundamental processes within 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 the interaction of molecules with light, such as smog formation or damage to the ozone layer.”

Source: Sebastian Zentilomo

Conical intersection phenomenon

In particular, the research team witnessed a single interference pattern atom caused by a common geometric structure in chemistry called “cone intersection”.

Conical intersections are known throughout chemistry and are essential in fast photochemical processes such as light-gathering in human vision or photosynthesis.

Chemists have attempted to directly observe such geometric processes in chemical dynamics since the 1950s, but direct observation of them has been impossible due to the extremely short time frames.

Vanessa Olaya Agudelo and Christophe Valahu

Lead authors Vanessa Olaya Agudelo and Dr. Christophe Valahu in front of the experiment’s quantum computer at the Sydney Nascience Hub. Source: Stefanie Zingsheim/University of Sydney

To get around this problem, quantum researchers from the School of Physics and the School of Chemistry conducted an experiment using a quantum computer with trapped ions in a completely new way. This allowed them to design and map this very complicated problem on a relatively small quantum device, and then slow the process down 100 billion times.

The results of their research were published on August 28 in the journal The Chemistry of Nature.

“In nature, the whole process is completed in 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 chemical dynamics from femtoseconds to milliseconds. This enabled significant observations and measurements to be made.

“It’s never been done before.”

A wave packet evolving around a conic intersection

A wave packet evolving around a conical intersection, measured experimentally using a trapped ion quantum computer at the University of Sydney.
To observe how the wave packet behaves around a simulated conical intersection, the researchers used a single trapped ion – a single charged ytterbium atom trapped in a vacuum by electric fields.
They were then controlled and measured using a complex and precise sequence of laser pulses.
A mathematical model was then introduced to describe the conical intersections in the system of trapped ions.
The ion was then allowed to evolve around the designed conical intersection.
The researchers then created a video of the ion evolution around the conical intersection (see GIF). Each frame of the GIF represents an image representing the probability of finding the ion in a specific set of coordinates.
Source: University of Sydney

The role of quantum technology

Joint lead author Dr. Christophe Valahu of the School of Physics said: “Until now, we have not been able to directly observe the dynamics of the ‘geometric phase’; this is happening too fast to study experimentally.

“Using quantum technologies, we solved this problem.”

Dr Valahu said it was like simulating the air system around an aircraft wing in a wind tunnel.

“Our experiment was not a digital approximation of the process – it was a direct analog observation of quantum dynamics evolving at the speed we could observe,” he said.

In photochemical reactions such as photosynthesis, where plants draw energy from the sun, molecules transfer energy at lightning speed, creating exchange areas called conical intersections.

This study slowed down the dynamics of a quantum computer and revealed distinctive features predicted – but never seen before – associated with conical intersections in photochemistry.

Collaboration and future implications

Co-author and leader of the research team, Associate Professor Ivan Kassal from the University of Sydney’s Department of Chemistry and Nano Institute, said: “This exciting result will help us better understand ultrafast dynamics – how molecules change over the fastest timescales.

“It’s amazing that at the University of Sydney we have access to the country’s best programmable quantum computer to run these experiments.”

The quantum computer used to conduct the experiment is located in the Quantum Control Laboratory of Professor Michael Biercuk, founder of the quantum startup Q-CTRL. The experimental work was conducted by Dr. Ting Rei Tan.

Dr Tan, co-author of the study, said: “This is a fantastic collaboration between chemical theorists and experimental quantum physicists. We are using a new approach in physics to tackle a long-standing problem in chemistry.”

Reference: “Direct observation of geometric phase interference in dynamics around a conical intersection” by C. H. Valahu, V. C. Olaya-Agudelo, R. J. MacDonell, T. Navickas, A. D. Rao, M. J. Millican, J. B. Pérez-Sánchez, J. Yuen-Zhou, M. J. Biercuk, C. Hempel, TR Tan and I. Kassal, 28 August 2023, The Chemistry of Nature.
DOI: 10.1038/s41557-023-01300-3

The research was funded by grants from the US Office of Naval Research; US Army Research Office Physical Sciences Laboratory; activity in the field of advanced US intelligence research projects; Lockheed Martin; Australian Defense Science and Technology Group, Sydney Quantum; partnership award from the University of Sydney and the University of California, San Diego; H. and A. Harley; and from the computing resources of the Australian Government’s National Computing Infrastructure.


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