(Independent)
Quantum computers could finally be made at large scale after a number of major breakthroughs, the scientists behind them have announced.
The new research shows that it is possible to make robust and reliable silicon-based quantum computers, that would be compatible with the existing manufacturing technology we have.
Three separate papers in Nature together show that such silicon-based quantum processors are dependable and efficient enough that they could be made and used in the real world.
Each of the three papers show quantum computers that are more than 99.9 per cent error free, far above the 99 per cent threshold considered as the standard for fault-tolerant computers. As such, they could finally be ready to be used for actual applications.
“When the errors are so rare, it becomes possible to detect them and correct them when they occur,” said Andrea Morello from the University of New South Wales, the leader of one of those three pieces of research. “This shows that it is possible to build quantum computers that have enough scale, and enough power, to handle meaningful computation.”
Professor Morello’s is presented in Nature alongside another paper from a team in the Netherlands, and another from Japan.
Quantum computers, if they work, are expected to change the world, offering vastly more computing power and different ways of doing calculations than was ever possible before. Researchers across the world are racing to build larger quantum systems, of the scale and complexity required for useful applications.
But that work has been hampered by a whole host of difficulties. One of the problems is the noise generated in the qubits that are at the heart of the technology, which makes them prone to errors – and as the number of qubits increases, so does that noise, making it difficult to scale up the systems.
For them to actually be useful, researchers believe that a system would be required to hit a threshold of at least 99 per cent. Until now, scientists have only done that in other kinds of circuits, but they are difficult to build up to enough of a scale to actually make the computers both reliable and large-scale enough to be useful.
Through a variety of new breakthroughs, however, the researchers behind the new paper were able to reach that threshold and do it using technology which can already be produced at large scales, given it is similar to the semiconductor fabrication that happens today for classical computers.
Scientists hope that the research now shows that silicon can be used to make successful quantum computers – and that they can now get to work designing them to be larger and more capable.
“You typically need error rates below 1 per cent, to apply quantum error correction protocols,” said Professor Morello. “Having now achieved this goal, we can start designing silicon quantum processors that scale up and operate reliably for useful calculations.”