Observation of subdiffusion of a disordered interacting system

TL;DR

This paper investigates how matter-waves in a disordered system exhibit subdiffusive transport when interactions are introduced, combining experiments, simulations, and models to understand the underlying mechanisms.

Contribution

It provides experimental evidence and theoretical analysis of subdiffusion in a disordered Bose-Einstein condensate with interactions, emphasizing the role of disorder correlations.

Findings

Observation of slow, subdiffusive expansion of matter-waves

Confirmation that subdiffusion results from interaction-assisted hopping

Highlighting the influence of disorder correlation on transport behavior

Abstract

We study the transport dynamics of matter-waves in the presence of disorder and nonlinearity. An atomic Bose-Einstein condensate that is localized in a quasiperiodic lattice in the absence of atom-atom interaction shows instead a slow expansion with a subdiffusive behavior when a controlled repulsive interaction is added. The measured features of the subdiffusion are compared to numerical simulations and a heuristic model. The observations confirm the nature of subdiffusion as interaction-assisted hopping between localized states and highlight a role of the spatial correlation of the disorder.