Observation of the Anderson metal-insulator transition with atomic matter waves: Theory and experiment

Using a cold atomic gas exposed to laser pulses-a realization of the chaotic quasiperiodic kicked rotor with three incommensurate frequencies-we study experimentally and theoretically the Anderson metal-insulator transition in three dimensions. Sensitive measurements of the atomic wave function and the use of finite-size scaling techniques make it possible to unambiguously demonstrate the existence of a quantum phase transition and to measure its critical exponents. By taking proper account of systematic corrections to one-parameter scaling, we show the universality of the critical exponent nu=1.59 +/- 0.01, which is found to be equal to the one previously computed for the Anderson model.