New 'pendulum' for the ytterbium clock
The faster a clock ticks, the more precise it can be. Due to the fact that lightwaves vibrate faster than microwaves, optical clocks can be more precise than the caesium atomic clocks which presently determine time. The Physikalisch-Technische Bundesanstalt (PTB) is even working on several of such optical clocks simultaneously. The model with one single ytterbium ion caught in an ion trap is now experiencing another increase in accuracy. At PTB, scientists have succeeded in exciting a quantum-mechanically strongly "forbidden" transition of this ion and in particular in measuring it with extreme accuracy. The optical clock based on it is exact to 17 digits after the decimal point. The results are published in the current edition of the scientific journal Physical Review Letters.