Charles Darwin worried that the fossil record looked strangely abrupt, with complex animals appearing in a geological instant instead of gradually unfolding over deep time. A new idea about how ...

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 ...

Graphic illustrating the difference in energy between running a quantum clock (left: a single electron hopping between two nanoscale regions) and reading the ticks of the clock (right). The energy ...