From nature.com >
Quantum computing has long seemed like one of those technologies that are 20 years away, and always will be. But 2017 could be the year that the field sheds its research-only image.
Computing giants Google and Microsoft recently hired a host of leading lights, and have set challenging goals for this year. Their ambition reflects a broader transition taking place at start-ups and academic research labs alike: to move from pure science towards engineering.
“People are really building things,” says Christopher Monroe, a physicist at the University of Maryland in College Park who co-founded the start-up IonQ in 2015. “I’ve never seen anything like that. It’s no longer just research.”
Google started working on a form of quantum computing that harnesses superconductivity in 2014. It hopes this year, or shortly after, to perform a computation that is beyond even the most powerful ‘classical’ supercomputers — an elusive milestone known as quantum supremacy. Its rival, Microsoft, is betting on an intriguing but unproven concept, topological quantum computing, and hopes to perform a first demonstration of the technology.
The quantum-computing start-up scene is also heating up. Monroe plans to begin hiring in earnest this year. Physicist Robert Schoelkopf at Yale University in New Haven, Connecticut, who co-founded the start-up Quantum Circuits, and former IBM applied physicist Chad Rigetti, who set up Rigetti in Berkeley, California, say they expect to reach crucial technical milestones soon.
Academic labs are at a similar point. “We have demonstrated all the components and all the functions we need,” says Schoelkopf, who continues to run a group racing to build a quantum computer at Yale. Although plenty of physics experiments still need to be done to get components to work together, the main challenges are now in engineering, he and other researchers say. The quantum computer with the most qubits so far — 20 — is being tested in an academic lab led by Rainer Blatt at the University of Innsbruck in Austria.
Whereas classical computers encode information as bits that can be in one of two states, 0 or 1, the ‘qubits’ that comprise quantum computers can be in ‘superpositions’ of both at once. This, together with qubits’ ability to share a quantum state called entanglement, should enable the computers to essentially perform many calculations at once. And the number of such calculations should, in principle, double for each additional qubit, leading to an exponential speed-up.
This rapidity should allow quantum computers to perform certain tasks, such as searching large databases or factoring large numbers, which would be unfeasible for slower, classical computers. The machines could also be transformational as a research tool, performing quantum simulations that would enable chemists to understand reactions in unprecedented detail, or physicists to design materials that superconduct at room temperature. [….]