A team of engineers at the University of New South Wales have built a quantum logic gate in silicon which makes calculations between two quantum bits or `qubits’ of information possible.
According to the team, silicon quantum computers will become a reality.
UNSW scientia professor and director of the Australian National Fabrication Facility, Andrew Dzurak, said it will be much easier to manufacture a full scale processor chip in silicon.
“This makes the building of a quantum computer much more feasible, since it is based on the same manufacturing technology as today’s computer industry,” he said.
The advance represents the final physical component needed to realise the promise of super-powerful silicon quantum computers, which harness the science of the very small – the strange behaviour of subatomic particles – to solve computing challenges that are beyond the reach of even today’s fastest supercomputers.
In classical computers, data is rendered as binary bits, which are always in one of two states: 0 or 1. However, a quantum bit can exist in both of these states at once, a condition known as a superposition. A qubit operation allows many computations to be performed in parallel.
“If quantum computers are to become a reality, the ability to conduct one- and two-qubit calculations are essential,” said Dzurak, who jointly led the team in 2012 who demonstrated the first ever silicon qubit, also reported in <i>Nature</i>
The result means that all of the physical building blocks for a silicon-based quantum computer have now been successfully constructed, allowing engineers to begin the task of designing and building a functioning quantum computer.
The UNSW engineers have reconfigured the silicon transistors that are used to define the bits in existing silicon chips, and turned them into qubits.
“The silicon chip in your smartphone or tablet already has around one billion transistors on it, with each transistor less than 100 billionths of a metre in size,” said Dr Menno Veldhorst, a UNSW Research Fellow and the lead author of the <i>Nature</i> paper.
“We’ve morphed those silicon transistors into quantum bits by ensuring that each has only one electron associated with it. We then store the binary code of 0 or 1 on the ‘spin’ of the electron, which is associated with the electron’s tiny magnetic field,” he added.
Dzurak said the team had recently “patented a design for a full-scale quantum computer chip that would allow for millions of our qubits, all doing the types of calculations that we’ve just experimentally demonstrated.”
He added that a key next step for the project is to identify the right industry partners to work with to manufacture the full-scale quantum processor chip.
According to Dzurak, a full-scale quantum processor would have major applications in the finance, security and healthcare sectors, allowing the identification and development of new medicines by greatly accelerating the computer-aided design of pharmaceutical compounds, the development of new, lighter and stronger materials spanning consumer electronics to aircraft; and faster information searching through large databases.