When the microwave signal exactly matches the material’s resonance frequency — 9.192631770 GHz, in the case of cesium — the number of atoms changing state will be at a maximum, so you know ...

Maybe that’s even more than half of the fun. [CuriousMarc] got an HP 5061A Cesium clock, a somewhat famous instrument as the model that attempted to prove the theory of relativity. The reason?

We’re proud to partner closely with them, making our industry-first high-performance optical cesium product a direct contributor to their UTC system and enhancing the accuracy and stability of ...