Atom interferometry

Article By:

Hohensee, Michael A. Department of Physics, University of California, Berkeley, California.

Lan, Shau-Yu Department of Physics, University of California, Berkeley, California.

Müller, Holger Department of Physics, University of California, Berkeley, California.

Last reviewed:2014

DOI:https://doi.org/10.1036/1097-8542.YB140360

An atom interferometer is a device that uses the wave–particle duality of quantum mechanics: A particle—for example, an atom—can be described as a wave whose amplitude is large at places where the atom is likely to be found. In an interferometer, such a wave can simultaneously explore two or more paths. The waves that emerge from either path can add or cancel, changing the number of detected atoms in a way that depends on interactions encountered by the waves along the paths. Atom interferometers have been used to measure rotations and accelerations, including the acceleration of free fall and its position dependence. Thus, they can be applied in geology and mineral exploration as well as navigation. They have also been used to measure fundamental constants, and for some of the most stringent tests of fundamental theories of physics such as quantum mechanics and general relativity.

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