Propagation of Ultracold Atoms in Disorder: Diffusion and Localization Phenomena

Speaker: Jeremie Richard
Affiliation: Laboratoire Charles Fabry, Institut d’Optique CNRS, Univ. Paris-Saclay

Abstract: Coherent transport in disordered media has been a thriving topic for many decades. Started with the seminal paper by Anderson in 1958, introducing the possibility of strong localization of waves, the interest is still alive nowadays as open questions remain.   A renewed perspective is given by the use of ultracold atomic systems for the study of wave propagation in disorder, which rouse a lot of interest over the past decade. Anderson Localization was observed with ultracold atoms, allowing for a precise study these phenomena.  We will here focus on the first observation of a weak localization phenomenon using ultracold atoms: the Coherent Backscattering (CBS), i.e. the enhancement of the scattering probability in the backward direction. We will show that this phenomenon can be finely monitored thanks to the precision of ultracold atoms experiments leading to the controlled suppression and revival of the CBS.

Finally, the precise measurement of the elastic scattering time will be presented as it is an essential elementary parameter for diffusion. This study allows for a new quantitative comparison with diffusion models, including Born approximation calculations. It also gives an unambiguous signature of the peculiar behavior of the diffusion in optical speckle disorder.

Biography:  After an Ingeneering Degree in Optical Sciences and a Master Degree in Nanosciences from the Institut d’Optique and the Paris-Sud (now Paris-Saclay) University (Palaiseau – France), Jeremie Richard obtained his PhD thesis in Experimental Physics in the field of Atomic, Molecular and Optical Physics in the group of Alain Aspect at the Institut d’Optique. His work was based on the study of the propagation of ultracold atoms (i.e. Bose-Einstein Condensates) in optical disorder, including phenomena such as Anderson Localization, Weak Localization and Diffusion.

For more information, contact Prof. Aydogan Ozcan ()

Date(s) - Sep 28, 2016
10:30 am - 11:30 am

E-IV Tesla Room #53-125
420 Westwood Plaza - 5th Flr., Los Angeles CA 90095