World's most accurate clock built in Germany

Physicists in Germany have built the most accurate clock on earth. This atomic clock breaks all previous records to achieve unprecedented levels of accuracy.

This clock attains the accuracy which had only been predicted theoretically so far. The single-ion clock is built by the atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB).

As early as 1981, Hans Dehmelt, who was to be awarded a Nobel Prize later, had already developed the basic notions of how to use an ion kept in a high-frequency trap to build a clock which could attain the then unbelievably low relative measurement uncertainty in the range of 1E-18.

The invention of this atomic clock makes PTB scientists the first research group in the world to have built an optical single-ion clock. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18.

The clock’s pendulum consists of atoms which are excited into resonance by microwave radiation (1E10 Hz). The definition and realisation of the SI unit of time, the second, is currently based on cesium atomic clocks.

This is considered as certain that a future redefinition of the SI second will be based on an optical atomic clock. What makes them much more stable is their considerably higher excitation frequency (1E14 to 1E15 Hz).

The accuracy achieved with the ytterbium clock is approximately a hundred times better than that of the best cesium clocks.