Coherent back scattering and Anderson Localization of ultra cold atoms

Summary form only given. An ensemble of ultra cold atoms released in a well-chosen disordered optical potential is a system that offers a privileged way to directly observe Anderson Localization. Localization has been observed in 1D [1,2] and 3D [3,4], while 2D experiments are promising [5]. Theory supports the conclusion that what we observe is AL [6,7], but a smoking gun of the role of coherence is still missing. Recently, we have observed CBS [8] (see Figure), an indisputable coherent effect in quantum transport, related to the first order manifestation of localization (weak localization). Anderson Localization is a research field where many theoretical questions remain open. In particular, when there is interaction between particles, the corresponding quantum many-body problems are exceedingly difficult to solve. We thus plan to implement controlled interactions between atoms in our system, using Feschbach resonances, in order to provide answers to such problems. The system will then deserve the name of "quantum simulator" in the sense used by Feynman in his pioneering paper [9].