Atom interferometry in an optical lattice

Precision quantum control and long-lasting coherence are instrumental in quantum metrology and sensing. Atom interferometers are powerful in probing fundamental physics and everyday sensing but have been limited to measurement times of a few seconds by using atoms in free fall. We will discuss interferometers with atoms suspended for an unprecedented 70 seconds in an optical lattice. This method is particularly well suited for probing localized potentials. I will show how we optimize the gravitational sensitivity of the lattice interferometer and use a system of signal inversions and switches to suppress and quantify systematic effects. This enables us to measure the attraction of a miniature source mass with an accuracy of 6.2 nm/s², less than a billionth of Earth’s gravity and four times as good as the best similar measurements with freely falling atoms. We will then discuss applications to atomic gravimeters in the field as well as precision measurement.