Matterwave interferometers based on cold atoms are commonly used as gravimeters. They reach accuracies of up to 10⁻⁹g and are nowadays even commercially available.

We have demonstrated a compact quantum gravimeter, which employs an atom chip for the rapid and efficient creation of Bose-Einstein condensates (BEC). At the same time, the atom chip serves for complete state preparation of the atomic cloud and as a retroreflector for the laser beam to create an optical lattice. With the lattice, we split, redirect, and recombine the BEC to form a Mach-Zehnder interferometer and measure the local gravitational acceleration.

To extend the interferometer time and increase the device’s sensitivity, we employ the optical lattice for an innovative launch mechanism. In this way, we acquire an intrinsic sensitivity of Δg/g = 10⁻⁷, while keeping all atom-optical operations in a volume of less than a one-centimeter cube.

S. Abend et. al. Atom-Chip Fountain Gravimeter Phys. Rev. Lett. 117, 203003 (2016)