Some progress of the weak equivalence principle test

Abstract

The Weak Equivalence Principle (WEP) together with Local Position Invariance (LPI) and Local Lorentz Invariance (LLI) forms the Einstein Equivalence Principle (EEP), which is one of the basic assumptions of Einsteins General Relativity. However, most of the theories trying to unify the gravitation with the quantum world, which is mostly described by the Standard Model, indicate some violation of the WEP. So the discovery of violation of the WEP would have a very important scientific significance. Testing the WEP with the highest possible precision is always a frontier issue in the world. This paper introduces almost all the ways of testing the WEP all over the world, including using the simple pendulum, torsion balance, free fall and lunar laser ranging. Whats more, a lot of space missions have been proposed to test the WEP with a higher precision by many groups and institutions. The latest progress of these tests will also be described here.