Through building a quantum logic gate in silicon for the first time, an Australian team of engineers has made it possible to calculate between two quantum bits (qubits) of information and therefore cleared the last hurdle in making silicon quantum computing happen.

The significant milestone – dubbed a “game changer” by team leader Andrew Dzurak, director of the Australian National Fabrication Facility and professor at the University of New South Wales (UNSW) – is reported in the journal Nature last Oct. 5.

The team from UNSW claims to have demonstrated a two-qubit logic gate, a quantum computer’s central building block, and have “significantly done it in silicon.”

“[W]e believe it will be much easier to manufacture a full-scale processor chip than for any of the leading designs, which rely on more exotic technologies,” explained Dzurak, highlighting that they use practically the same device technology as computer chips in existence today.

UNSW research fellow Menno Veldhorst is the lead author of the Nature study. Other experts in the team include research fellow Henry Yang and Associate Professor Andrea Morello, both from UNSW's School of Electrical Engineering and Telecommunications, and Professor Kohei M. Itoh of Keio University in Japan, who provided specialized silicon wafers for the endeavor.   

This breakthrough is believed to make building a quantum computer much more viable, as it follows the manufacturing technology of the computer sector today.

The research is deemed to break down the final barrier in realizing the potential of super-powerful silicone quantum computers, using subatomic particles in addressing computing challenges that even the fastest supercomputers at present cannot solve.

Data is rendered as binary bits in classical computers – always either in 0 or 1 state. Also known as a superposition, a qubit can exist in both states at once and operates in a way that allows numerous computations to be done in parallel.

Dzurak said that being able to conduct one and two qubit calculations are important in making quantum computing happen.

The team enabled two qubits to “talk” to each other and created a logic gate with the use of silicon for the first time. This development successfully completes all of the physical elements of a silicone-based quantum computer, enabling engineers to start designing and creating the computer previously quite impossible in physical reality, according to UNSW engineering dean Professor Mark Hoffman.

A full-scale quantum processor is expected to benefit multiple industries that include security, finance and healthcare. It allows, for instance, the development of new medications through the greatly accelerated computer-aided design of pharmaceutical compounds to help optimize trials and error testing.

The technology is devised, tested and patented by the UNSW team, who are now looking for industry partners to begin the production of the full-scale quantum processor chip.

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