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Chip-scale atomic clocks

The most accurate caesium clocks based on the caesium frequency of 9.19 GHz have an accuracy between 10 –10. Unfortunately, they are big and only available in large metrology labs and not useful for factories or industrial environments that would use an atomic clock for GPS accuracy but cannot afford to build a whole metrology laboratory for one atomic clock. Researchers have designed a strontium optical clock that can be moved around in an air-conditioned car trailer.