Keeping track of time seems simple. A watch ticks, a pendulum swings, and a calendar flips. But at the quantum level, marking time is far more complicated — and far more expensive than anyone expected ...

Quantum timekeeping is supposed to be the ultimate in efficiency, with tiny devices that tick using the rules of quantum mechanics instead of swinging pendulums or vibrating quartz. Yet new work on a ...

Scientists built a tiny clock from single-electron jumps to probe the true energy cost of quantum timekeeping. They discovered that reading the clock’s output requires vastly more energy than the ...