A dual-magneto-optical-trap atom gravity gradiometer for determining the Newtonian gravitational constant

Abstract

As part of a program to determine the gravitational constant G using multiple independent methods in the same laboratory, an atom gravity gradiometer is being developed. The gradiometer is designed with two magneto-optical traps to ensure both the fast simultaneous launch of two atomic clouds and an optimized configuration of source masses. Here, the design of the G measurement by atom interferometry is detailed, and the experimental setup of the atom gravity gradiometer is reported. A preliminary sensitivity of 3 × 10^-9 g/Hz to differential gravity acceleration is obtained, which corresponds to 99 E/Hz (1 E = 10^-9 s^-2) for the gradiometer with a baseline of 0.3 m. This provides access to measuring G at the level of less than 200 parts per million in the first experimental stage.