Trapped ions for quantum metrology

Optical clocks enable frequency measurements with a systematicfractionaluncertainty of 10^-18 and lower. These clocks use opticaltransitions ofcold trapped ions in radio-frequency traps or cold ensembles oftrappedneutral atoms as frequency references with long-term stability.There isan increasing demand for commercially available precise clocksfor bigdata, stock exchange, and positioning systems. Further,ultra-precise clockscan be used to test General Relativity, search for new physics,and geodeticmeasurements. Todate, precise clocks are realized mainly inlaboratoryexperiments and require highly trained operators. We aredeveloping chip-basedion traps for portable optical clocks that can be used for field measurements,as well as multi-ion clocks that enable faster precisionmeasurements.In this talk, we will give an update on ion trap technologiesthat willhelp to make the clocks smaller. This includes more compactelectricalconnections and space-saving