Experimental observation of the Anderson transition with atomic matter waves
Résumé
Phase transitions are major phenomena in physics. Of particular interest in modern physics is the metal-insulator Anderson transition in disordered systems, ultimately due to the interplay between quantum interference and disorder. We present the first experimental observation of the Anderson transition using atomic matter waves. The metal-insulator transition plays a central role in the study of quantum disordered systems, and has been extended from its original solid-state scope to many different fields, including dynamical systems, electromagnetic radiation, acoustics, biology and even cosmology. Many studies have also pointed out strong analogies between cold atoms trapped in optical lattices and condensed matter. Using an atom-optics system formally equivalent to the 3D Anderson model we unambiguously demonstrate the Anderson transition. Sensitive measurements of the atomic dynamics and the use of finite-size scaling techniques make it possible to extract both the critical disorder strength and the critical exponent of the transition. In doing so, we make use of the physical concepts underlying phase transition phenomena: universality classes (i.e., the insensitivity of the critical phenomena to the microscopic properties of the system) and renormalization (which describes the scaling laws in the vicinity of the transition).
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