Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of gravitational field or the properties of matter responsible for its creation are of interest. The term gravimetry or gravimetric is also used in chemistry to define a class of analytical procedures, called gravimetric analysis relying upon weighing a sample of material.
Atom interferometry: In light-pulse atom interferometers, atomic matter waves are split and recombined using pulses of laser light. The splitting occurs because when an atom interacts with the photons of a laser beam, it exchanges the momentum of a number of photons. The atom may thus continue on either of two spatially separate paths, the interferometer arms. When the paths are recombined, the probability that the atom is found depends upon the phase difference between them, which determines whether the matter waves will add or cancel. This phase is shifted by the atom’s coupling to electromagnetic fields, gravity, inertial forces, and other influences. By selecting the geometry of the interferometer, the atomic species, and its quantum state, one can maximize the wanted influence and minimize others. Advances in the control of the quantum state of atoms and photons have led to an extraordinary sensitivity and accuracy.