Quantum computing device sees exponential increase in speed

New Scientist : Another advance has been made in the development of a quantum computer. Fabio Sciarrino of the Sapienza University of Rome and colleagues have been working on a quantum machine that implements an approach known as boson sampling. Their machine is based on a 19th-century counting device called the Galton box, which demonstrates statistical distributions, or bell curves. Invented by Francis Galton, the box consists of a vertical board with rows of pins through which balls are dropped and collect at the bottom in bins. The quantum version uses photons that travel along a network of intersecting channels in an optical chip, collide, and change direction. Sciarrino and coworkers have now increased the speed of their device, previously demonstrated in 2012, by increasing the number of photon sources from one to six. Although the improvement is promising, researchers say there’s still a long way to go before quantum computers surpass classical ones.