STAGE Towards a spectroscopic study of the Anderson quantum phase transition

Anderson localization is an intriguing phenomenon of wave propagation in random media, where destructive
interference between various diffusion paths yields to a complete suppression of transport. It has attracted a lot of
attention over past decade, from electronic to classical waves (light, acoustic and even seismic waves). However open
questions remain, especially in 3D where an insulator to metal (localization to delocalization) quantum phase transition
occurs. In this context, studying the propagation of ultracold atoms in optical random potentials offers new perspectives
to study this phenomenon in a renewed perspective. Many landmark experiments have proven the great potential of
these systems, especially in the team at IOGS.
After the demonstration of Anderson localization in various configurations, the team is currently developing a new
method in order to study the 3D Anderson quantum phase transition (V. Volchkov et al. Phys. Rev. Lett. 120, 060404,
2018). It is based on the use of two laser speckle fields, created at slightly different detuning compared to an atomic
transition, in order to realize a state dependent disorder. The goal of the internship will be to finalize the
implementation of this new kind of disordered potential, to characterize it and to participate to the evolution of the
experiments on the day-to-day basis. We anticipate a beginning of the investigation of the 3D Anderson phase
transition during the internship and the student will participate to acquisition, treatment and understanding of the data.
This proposal is mainly dedicated to experiments. However, a theoretical part could be envisioned with the theoretician
Marcel Filoche from laboratory PMC at Polytechnique. He is indeed developing, together with the mathematician
Svitlana Mayroboda (US), a very promising theoretical framework to understand Anderson localization.