Physics Today
Three-dimensional Anderson localization
Abstract
Anderson localization (AL) is a ubiquitous interference phenomenon in which waves fail to propagate in a disordered medium.We observe three-dimensional AL of non-interacting ultracold matter by allowing a spin-polarized atomic Fermi gas to expand into a disordered potential.A two-component density distribution emerges consisting of an expanding mobile component and a nondiffusing localized component.We extract a mobility edge that increases with the disorder strength, whereas the thermally averaged localization length is shown to decrease with disorder strength and increase with particle energy.These measurements provide a benchmark for more sophisticated theories of AL.Wave propagation in disordered media is affected by scattering from random impurities.When those scattered waves self-interfere destructively, a phenomenon known as Anderson localization (AL) can arise (1).AL occurs in a wide variety of classical and quantum materials, impacting the transport of light (2, 3), acoustic (4), and matter (5, 6) waves.Localization is known to affect electrical conductivity in solids as a result of scattering from impurities and 1