The quantum Y2K moment

The advent of quantum computers threatens many of the encryption systems that keep online communications secure and make e-commerce possible. Margaret Harris investigates plans to make the Internet safe for the quantum era

Winfried Hensinger wants to build a computer the size of a football pitch. He’s aware that the idea may be a tough sell. Scientists and engineers have laboured for decades to transform the room-sized machines of the 1940s and 1950s into devices that fit on a desk, in the palm of your hand, and even – as with a chip unveiled at IBM last March – inside a grain of salt. Why would anyone take such a gigantic step backwards?

The answer lies in the architecture of Hensinger’s proposed machine. Instead of performing calculations with classical 0s and 1s, the computer he and colleagues at the University of Sussex in the UK hope to build would exploit the quantum properties of a billion ytterbium ions. Hensinger’s blueprint calls for these ions to be kept aloof from their environment with magnets and individually shuttled into interaction zones within a vast grid of microfabricated traps, using a field of microwave radiation to control their movements. The result, he says, would be a computer that can unravel “tremendously complicated problems that would take billions of years to solve on even the fastest supercomputers”.

Hensinger’s dream is exceptional in its scope, but his goal is far from unique. In recent years, governments and corporations such as IBM and Google have poured billions into quantum-computing research. Thanks to their investments, and the efforts of thousands of scientists worldwide, it is no longer absurd to think that a large-scale quantum computer will – somewhere, and in some form – become a reality. It won’t happen overnight, of course; today’s state-of-the-art devices boast no more than a few dozen qubits, and Hensinger acknowledges that it would take a “massive” amount of work (and around £100m) to scale his current prototype up to the billion-qubit level. But he insists that overcoming these challenges is a matter of “engineering, not physics”, and the mood among quantum physicists is generally buoyant. Few would bet against a universal quantum computer emerging sometime in the next 20 years. ..Read More..

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