Paper detail

Quantum test of the Universality of Free Fall using rubidium and potassium

We report on an improved test of the Universality of Free Fall using a rubidium-potassium dual-species matter wave interferometer. We describe our apparatus and detail challenges and solutions relevant when operating a potassium interferometer, as well as systematic effects affecting our measurement. Our determination of the Eötvös ratio yields $η_{\,\text{Rb,K}}=-1.9\times10^{-7}$ with a combined standard uncertainty of $σ_η=3.2\times10^{-7}$.