UNSW team creates artificial atoms for quantum computing

Dr Andre Saraiva, Mr Ross Leon and Professor Andrew Dzurak in the UNSW lab where they ran the experiments on their quantum device. Photo: UNSW/Ken Leanfore

In a breakthrough for quantum computing, researchers from the University of New South Wales (UNSW) have created artificial atoms in silicon chips that offer improved stability for quantum computing, but could also be used in medicines and for reducing energy consumption.

“By using silicon CMOS technology (the technology used to manufacture all modern-day computer chips) we can significantly reduce the development time of quantum computers with the millions of qubits that will be needed to solve problems of global significance, such as the design of new medicines, or new chemical catalysts to reduce energy consumption,” Professor Andrew Dzurak, ARC Laureate Fellow and director of the Australian National Fabrication Facility at UNSW, said.

“The idea of creating artificial atoms using electrons is not new, in fact it was first proposed theoretically in the 1930s and then experimentally demonstrated in the 1990s – although not in silicon. We first made a rudimentary version of it in silicon back in 2013,” Dzurak said.

Dzurak explained that unlike a real atom, an artificial atom has no nucleus, but it still has shells of electrons whizzing around the centre of the device, rather than around the atom’s nucleus.

“But what really excites us about our latest research is that artificial atoms with a higher number of electrons turn out to be much more robust qubits than previously thought possible, meaning they can be reliably used for calculations in quantum computers. This is significant because qubits based on just one electron can be very unreliable.”

Professor Dzurak’s team was the first in the world to demonstrate quantum logic between two qubits in silicon devices in 2015, and has also published a design for a full-scale quantum computer chip architecture based on CMOS technology.

In a continuation of this latest breakthrough, the group will explore how the rules of chemical bonding apply to these new artificial atoms, to create ‘artificial molecules’. These will be used to create improved multi-qubit logic gates needed for the realisation of a large-scale silicon quantum computer.