After decades as laboratory curiosities, some of quantum physics’ oddest effects are beginning to be put to use, says Jason Palmer
PATRICK GILL, a director of the new Quantum Metrology Institute at Britain’s National Physical Laboratory (NPL) in south-west London and an expert in atomic clocks, points to a large table full of lenses and mirrors, vacuum chambers and electronics. “And there’s a smaller one over there,” he says.
NPL is part of a consortium of the planet’s official timekeepers. In all its atomic-clock laboratories, each of the flagship devices—some of which are huge—is flanked by a smaller one under construction. Miniaturisation is the name of the game. Here is one that fits into a standard electronics rack, 19 inches wide. Over there is a fist-sized gizmo designed to hold an atomic clock’s precious innards safe within a satellite.
The caesium atomic clock, developed at NPL, was arguably the world’s first quantum technology, though it was not labelled as such. The most common approach, first used in 1950, works by putting energy into atoms to create a “superposition” in which they are, in a measurable way, in more than one energy state at the same time—both excited and relaxed. Probing this strange condition reveals the “clock frequency” of those atoms—a constant for clocks on every continent, and the basis for a precise, internationally agreed definition of the second.
After decades of work in the laboratory, a raft of different devices and approaches relying on quantum-mechanical effects are now nearing market-readiness. It has taken so long mainly because the components that make them up had to be developed first: ever-better lasers, semiconductors, control electronics and techniques to achieve the low temperatures at which many quantum systems perform best.
Britain did not exploit the atomic clock’s discovery in the market. Instead, a year after the device was invented, it was commercialised by the National Company, an American firm. Given the potential of these new quantum technologies, this time commercialisation is on many minds. The NPL’s ever-smaller clocks are just one step towards marketable products that could vastly outdo GPS (which itself is an application of atomic timekeeping) in navigation, or help spot what lies underground. The era of quantum technology is almost here.
Read the full article on The Economist website.