A historic push for quantum computing

For the first time in the world, a quantum computer has been able to simulate nature at the atomic level using a chip that integrates all the components of a classical computer chip, but at the atomic scale.

A team from the University of New South Wales (UNSW Sydney) led by Professor Michelle Simmonsdesigned an atomic-level quantum processor to simulate the behavior of a small organic molecule, thus solving a challenge posed nearly 60 years ago by a theoretical physicist Richard Feynman.

Simmons recalls that in the 1950s, Richard Feynman said that we will never understand how the world works, and how nature works, unless we can begin to do it on the same scale. He adds, “If we can begin to understand the material at this level, we can design things that have not been done before.

The achievement, which came two years ahead of schedule, represents a major milestone in the race to build the world’s first quantum computer, and demonstrates that the quantum states of electrons and atoms in silicon can be controlled to a level they’ve never been before. It has been achieved before, according to the researchers.

Built-in Quantum Processor

It is an integrated quantum processor for accurately modeling the quantum states of a small molecule Organic polyacetylenewhich will help create new materials.

The breakthrough will help industries build quantitative models for a range of new products, such as pharmaceuticals, battery materials and catalysts, according to the Australian government.

Simmons and his team not only created what is essentially a working quantum processor, but also successfully tested it by modeling a small molecule in which each atom contains multiple quantum states, something a conventional computer would struggle to achieve.

This suggests that we are one step closer to using the power of quantum processing to understand more about the world around us, even on the smallest scale.

applied technology

He adds that to make this leap in quantum computing, the researchers used a scanning tunneling microscope (used to image surfaces at the atomic level) in an ultra-high vacuum (pressure below 10-7 mbar) to position quantum dots with sub-nanometer precision.

The location of each quantum dot must be exactly correct so that the circuit can simulate how electrons jump along a chain of single- and double-bonded carbons in a polyacetylene molecule.

The hardest parts were figuring out: exactly how many phosphorous atoms must be in each quantum dot; Exactly how far apart each point should be; Then he designed a machine that could place the tiny dots in exactly the right order on the silicon chip.

The final quantum chip contained 10 quantum dots, each consisting of a small number of phosphorous atoms. The carbon double bonds were simulated by placing a lower distance between the quantum dots compared to the single carbon bonds.

Polyacetylene was chosen because it is a popular model, and thus it can be used to show that the computer was correctly simulating the movement of electrons through the molecule.

Historic milestone

Simmons also points out that the development of quantum computers is on a path similar to that of classical computers: from the transistor in 1947 to an integrated circuit in 1958, and then to small computer chips that became commercial products, such as calculators, roughly five years later. “We are now replicating this roadmap for quantum computers,” he adds.

He explains, “We started with a monoatomic transistor in 2012. This latest result, made in 2021, is equivalent to an atomic-scale quantum integrated circuit, two years earlier. If we compare it with the development of classical computing, we expect that we should achieve a kind of the commercial results of our technology within five years.”

One advantage that this research brings is that the technology is scalable because it has been able to use fewer components in the circuit Control of qubitswhich are the basic parts of quantitative information.

“In quantum systems, you need something that creates the qubits, some kind of structure in the device that allows you to configure the quantum state,” says Professor Simmons.

The atoms that make up qubits

In our system, The atoms themselves create qubits, which requires fewer elements in circles. We only needed six metal gates to control the electrons in our 10-point system; In other words, we have fewer gates of the device’s active components.

He clearly points out the difference: “Most quantum computing architectures need roughly twice as many or more control systems to move electrons in a qubit structure.”

By requiring fewer tightly packed components, the amount of any interference with quantum states is reduced, allowing devices to be scaled up to create more complex and powerful quantum systems.

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Looking to the future, Professor Simmons and colleagues will explore larger compounds that may have been predicted theoretically, but have not yet been simulated or fully understood, such as high-temperature superconductors.

reference

Geometric topological states in atom-based semiconductor quantum dots. M. Kiczynski et al. Nature, Volume 606, pp. 694-699 (2022). DOI: https://doi.org/10.1038/s41586-022-04706-0