Australia''s first-ever quantum computer circuit is one that consists of all the essential components found on a classical computer chip, but at the quantum scale.
Nine years later, the significant discovery, published in Nature, was in the works.
"This is the most exciting discovery of my career," Michelle Simmons, head of Silicon Quantum Computing and head of the Center of Excellence for Quantum Computation and Communication Technology at UNSW, told ScienceAlert.
Simmons and her team crafted something that is essentially a functional quantum processor but they also successfully tested it by generating a small molecule in which each atom has multiple quantum states, something that a traditional computer would struggle to achieve.
Even at the darkest levels, this suggests we''re moving forward with the possibility of finally using quantum processing power to understand more about the world around us.
"In the 1950s, Richard Feynman said, "We''ll never understand how the world works, how nature works," Simmons told ScienceAlert.
"If we can start to understand materials at that level, we can do things that have never been accomplished."
"The question is: how do you actually control nature at that level?"
In the following year, the team started making the first ever quantum transistor.
(Atransistoris is a small device that controls electronic signals and forms only one component of a computer circuit. An integrated circuit is more complicated as it combines loads of transistors.)
In order to make this breakthrough in quantum computing, researchers used a scanning tunneling microscope in an ultra-high vacuum to position quantum dots with sub-nanometer accuracy.
So, the distribution of each quantum point must be exact, so that the circuit may re-imagine how electrons hop along a string of single- and double-bonded carbons in a polyacetylene molecule.
The trickiest part was figuring out: exactly how many atoms of phosphorus should be in each quantum dot; exactly how far apart each dot should be; and then developing a machine that might place the tiny dots in exactly the correct arrangement inside the silicon chip.
The quantum dots are too big, and the interaction between two areas becomes "too large" to independently control them, according to researchers.
If the dots are too small, then this is because each additional phosphorus atom may substantially alter the amount of energy it takes to add another electron to the dot.
The final quantum chip included ten quantum dots, each made up of a small number of phosphorus molecules.
By reducing the distance between the quantum dots, two carbon bonds were simulated.
Polyacetylene was chosen because it is a well-known technique and could therefore be used to demonstrate that the computer was correctly monitoring the movement of electrons through the molecule.
Because classical computers cannot model large molecules, quantities are required. They are just too complex.
For example, a classical computer would require 1086 transistors, which is "more transistors than there are atoms in the observable universe."
For a quantum computer, it would only require a processor with 286 qubits (quantum bits).
Because scientists have no understanding of how molecules function at the atomic scale currently, there''s a lot of guess work in the creation of new materials.
"One of the holy grails has always been making a high-temperature superconductor," Simmons said. "People simply don''t know the mechanism for it to work."
A further consideration for quantum computing is the study of artificial photosynthesis and how light is transformed to chemical energy through a complex of reactions.
A major issue quantum computers may be able to resolve is the creation of fertilizers. Triple nitrogen bonds are currently broken in hot conditions in the presence of an iron catalyst to produce fixed nitrogen for fertilizer.
Finding a different approach to improve fertilizer might save a lot of money and energy.
Simmons claims that moving from quantum transistor to circuit in just nine years is reminiscent of the original approach used by classical computers.
The first classical computer transistor was built in 1947. The first integrated circuit was built in 1958. These two inventions were 11 years apart, and Simmons'' team made the leap two years ahead of schedule.
This article was published in Nature.