Portable optical atomic clock for use as a gravity sensor
The University of Birmingham is developing a portable optical atomic clock that could be used as a gravity sensor as well as for navigation and timing, writes Steve Bush in UK plc reveals quantum 2.0 science, having visited the National Physical Laboratory.
Usually lab-sized, the Birmingham clock is already down to 1m across, and the aim is to reduce this to the size of a suitcase, while retaining as much as possible of the 100x accuracy improvement possible compared to microwave atomic clocks.
According to Einstein’s theory of relativity, the stronger the gravitational field, the slower time should pass. Optical clocks are now accurate enough to detect these differences.
Changing their height and measuring time differences should allow gravitational potential to be measured. Such a clock would prediction of things that depend on the Earth’s geoid – the shape of the surface of the seas if they were affected by gravitational force alone – rather than height from sea level, such as paths of missiles and levels of water in a dam.
They could also help produce a height reference system between different countries – which are current based on coastal sea levels, which can differ by tens of centimetres.
The University is also applying atom interferometers ot the gravity telescope challenge.
“Oil and mineral reservoirs go along with a density anomaly which for detection needs a combination of an acceleration sensor in addition to a good geoid reference,” said the University.
Image: University of Birmingham strontium atomic work bench