Gravitation and Cosmology

Dr. Claus Lämmerzahl

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Though general relativistic effects can be measured with very high precision, the gravitational constant – one of our most fundamental constants in physics – can be determined with very low precision only. In electrodynamics there are consistency relations between fundamental constants which are called metrological triangles. We show that such a concept of a metrological triangle can also be introduced in Einstein’s General Relativity. We show that it is possible to introduce a gravitational classical metrological triangle made of gravitational permittivities and permeabilities as well as of the speed of gravity. This allows to include more existing high precision tests to the exploration of the nature of gravity. As a result it is possible to improve the determination of Solar System general relativistic effects. Beyond this classical metrological triangle it is also possible to introduce a gravitational quantum metrological triangle. This is based on gravitational analogues of the Josephson effect and the quantum Hall effect. This quantum metrological triangle gives additional insight into gravity, suggests new laboratory tests for gravity, and also may allow a new definition of the kilogram.