Time-optimized atomic lensing mechanism for the source preparation of dual-species atomic gases in an atom-interferometric test of the weak equivalence principle

Abstract

In the atom-interferometric test of the weak equivalence principle (WEP) with multicomponent atomic gases, the difference in the center-of-mass positions between different components, as well as the difference in the center-of-mass velocities, leads to systematic uncertainties. An effective way to reduce these systematic uncertainties is to suppress such differences at the preparation stage of atomic sources. In this work, we propose an efficient strategy for preparing two-component gases with a perfectly spatial overlap of the center-of-mass positions and that of the velocities, according to a scheme of the time-optimized atomic lensing mechanism. The key of the time-optimized atomic lensing lies in a two-step quench process of the trap frequency, which is accessible in free-fall experiments by appropriately manipulating the trapping frequency and the center position of the trap. By taking a dual-species rubidium atomic gas as an example, our calculations indicate that the differences in the center-of-mass positions and velocities between $^{85}\mathrm{Rb}$ and $^{87}\mathrm{Rb}$ atoms are simultaneously eliminated, which provides an optimized starting point to test the WEP. An estimation of the systematic uncertainties is also presented. Our method can serve as a potential protocol for the preparation of atom sources in tests of the WEP with multicomponent atomic gases.