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 ...

It’s Friday, which means I have to wind up the clock on the wall. It’s my wife’s clock. She brought it from Poland, where it had originally been her paternal grandmother’s who lived with them when my ...

From left to right, Adam Kaufman, Nelson Darkwah Oppong, Alec Cao and Theo Lukin Yelin inspect an atomic optical clock at JILA. Imagine walking into a room where several different grandfather clocks ...