Atom Interferometry Test of the Weak Equivalence Principle in Space

The Atom Interferometry Test of the Weak Equivalence Principle in Space (Q-WEP) is devoted to a precise measurement of the effect of gravity on matter using an atom interferometer; it tests one of the fundamental pillars of Einstein’s Theory of General Relativity with high precision and thereby searches for hints of quantum effects in gravity, contributing to the exploration of one of the current frontiers in fundamental physics. The primary science objective is the test of the universality of the free propagation of matter waves to an uncertainty in the Eötvös parameter of 1 part in 1014 by interferometrically tracking the propagation of matter waves in the earth’s gravitational field. Secondary objectives are related to the demonstration of instrument capability for differential gravity measurements as well as differential acceleration measurements with ‘long’ free evolution times. The study has been carried out within the ESA’s General Studies Programme (GSP); a short outline of the activities performed is presented in this Executive Summary.