A group of Australian scientists have created the world’s first quantum circuit. It is a circuit that contains all the essential components found in a classical computing chip, but at a quantum computing scale. The team that has developed it has taken no less than nine years to develop it.
The team is spearheaded by quantum physicist Michelle Simmons, founder of the Silicon Quantum Computing company, where scientists work; and Director of the Center of Excellence for Quantum Computing and Communications Technology at UNSW.
In addition to creating the circuit, Simmons and his team have tested it, for which they have modeled a small molecule, in which each of its atoms has multiple quantum states. Something that a traditional computer would have a lot of difficulties to achieve.
It is not the first achievement in quantum computing achieved by this team. Already in 2012 they created the world’s first quantum transistor. That is, a very small device that is one of the basic components of a computer circuit. An integrated circuit is more complex, since it is made up of a group of transistors. To get the circuit, the scientists used a scanning tunneling microscope, which they embedded in a very high vacuum in order to place quantum dots with sub-nanometer precision.
The location of each quantum dot needed to be correct so that the circuit could reproduce how electrons jump on a string of single- and double-bonded carbons in a polyacetylene molecule. According to the team, the most complicated part of the construction has been discovering how many phosphorus atoms should go in each quantum dot, the exact separation distance of the dots, and the development of a machine that could place these small dots at the exact point within the quantum dot. silicon chip.
Also, if the points are too large, the interaction between two points becomes «too large to control independently“, according to the researchers. And if they’re too small, randomness kicks in, because each additional phosphorus atom can dramatically change the amount of energy needed to add another electron to the dot.
The final quantum chip contained 10 quantum dots, each not made from a small number of phosphorus atoms. Carbon double bonds were simulated by reducing the distance between the quantum dots that singly bond carbon. Polyacetylene was chosen because it is a well-known model, so it could be used to prove that the computer was correctly simulating the movement of electrons through the molecule.
For Simmons, who it has gone from the creation of a quantum transistor to a quantum circuit in nine years It follows the same roadmap that the inventors of classical computers had. The researcher has pointed out that the first transistor of a classical computer was created in 1947, and the first integrated circuit, in 1958. Therefore, it took eleven years to go from one to another. Her team, working on the same process but on quantum computing, has taken two years less to achieve it.