If the atomic clock in the University of Colorado Boulder’s JILA laboratory had been started when the earth came into existence, its time would still be perfect down to the very second today. Likewise, if the clock were reset now and kept running, it would likely outlast life on Earth.
Aye, there’s the rub. …and kept running. But it doesn’t — it only runs for a few hours. Which means my standard disclaimer applies: this isn’t a clock, it’s a (kick-ass awesome) stopwatch.
So when Jun Ye says “You can expect more new breakthroughs in our clocks in the next five to ten years.” what he means is that they will continue to push for even more stable clocks — greater levels of precision and, if these are going to become primary or secondary frequency standards, greater accuracy. They are not going to to be pushing the envelope with respect to robustness of the technology unless it furthers the goal of better accuracy/precision — that’s not really their job. It’s my job. (Yeah, I’m starting work on an optical clock)
A confusing this is that they mention a competitor’s clock and claim it uses Cesium, but the linked article says it also uses Strontium. When it says it measures time in a “non-standard and still unaccepted way” I think they are referring to the fact that it’s an optical transition, and not at the ~9.192 GHz transition that defines the second. But non-standard and unaccepted? Not so much — the Rubidium fountains I have helped build, and Hydrogen masers that are in widespread use don’t/can’t rely on that transition, and these clocks are reported to the international Bureau of Weights and Measures.
Those stumbles aside, the applications mentioned at the end — precise sensors for gravity, for example (I think “quantity” in that bit is an autocorrect casualty and is supposed to be “quantum”), but not so much for timekeeping.