A team led by the University of Melbourne has presented a new method to develop quantum computers reliably and affordably by incorporating atoms “one by one” into silicon wafers to build quantum devices.
According to a University of Melbourne spokesperson, the technique of building parts “atom by atom” is said to “create large-scale patterns of counted atoms that are controlled so that their quantum states can be manipulated, coupled and read.”
The findings were published in a Advanced materials article and were developed by Professor David Jamieson and his team at UNSW Sydney, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Leibniz Institute for Surface Engineering (IOM) and RMIT.
According Teacher Jamieson, the team’s goal is to develop a large quantum device with this scalable method.
“We believe we could ultimately make large-scale machines based on single-atom quantum bits using our method and taking advantage of manufacturing techniques that the semiconductor industry has perfected.” Teacher Jamieson said.
To develop the chip, researchers must have precision down to nanometers.
“The technique takes advantage of the precision of the atomic force microscope, which has a sharp cantilever that ‘touches’ the surface of a chip with a positioning accuracy of just half a nanometer, about the same as the separation between atoms in a silicon crystal. ”explained a spokesperson for the University of Melbourne.
During the process, the team “dropped” an atom through a hole in the cantilever to its correct position on the chip. The sound of the atom hitting the silicone allowed the researchers to know when the atom was in place, allowing them to build elements with individual atoms more precisely than in previous tests.
“An atom colliding with a piece of silicon produces a very weak click, but we have invented very sensitive electronics that are used to detect the click, it is greatly amplified and gives a strong signal, a strong and reliable signal.” Teacher Jamieson explained.
“That allows us to have a lot of confidence in our method. We can say, ‘Oh, there was a click.’ An atom has just arrived. “Now we can move the cantilever to the next location and wait for the next atom.”
Professor Andrea Morello of UNSW, co-author of the paper, explained that the resulting prototype was a qubit “chip”, which was then used in experiments to understand the scalability of the process.
“This will allow us to design quantum logic operations between large sets of individual atoms, while maintaining high-precision operations across the processor.” Teacher Morello said.
“Instead of implanting many atoms in random locations and selecting the ones that work best, they will now be placed in an ordered arrangement, similar to transistors in conventional semiconductor computer chips.“
Dr Alexander (Melvin) Jakob from the University of Melbourne, first author of the paper, explained that the equipment used was designed as part of an international collaborative process.
“We use advanced technology developed for sensitive X-ray detectors and a special atomic force microscope originally developed for the Rosetta space mission together with a comprehensive computer model for the trajectory of ions implanted in silicon, developed in collaboration with our colleagues in Germany.” said Dr. Jakob.
“With our Center partners, we have already produced breakthrough results on single-atom qubits made with this technique, but the new discovery will accelerate our work on large-scale devices.”
Quantum computers are expected to be able to process new ways to crack cryptography, optimize finances, and potentially even develop vaccines.
The University of Melbourne project was supported by the Australian Research Council’s Center of Excellence in Quantum Computing and Communication Technology, the US Army Research Office and a grant from the Australian Research and Infrastructure Fund. the University of Melbourne. The project used Australia’s National Manufacturing Facility at the Melbourne Nanofabrication Center to carry out the experimentation.
[Related: Thales enters quantum technology partnership]
