Shining Zhu

A pendulum that almost nothing can knock off balance (not shaking, not heat, not magnetic fields) because it is hidden in the very heart of the atom. That is the kind of pendulum physicists used when they first switched on a nuclear clock. Previously, the best clocks, optical ones, relied on electron transitions.

An ordinary random network is like a road map: to connect four cities with a complex interchange, you need to lay down many highways. In the quantum world, things are different.