Freiburg 2024 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 15: Poster I

A 15.9: Poster

Dienstag, 12. März 2024, 17:00–19:00, Tent A

Diffusion of single ultracold atoms in an accelerated optical lattice — •Silvia Hiebel, Daniel Adam, Florian Schall, Sabrina Burgardt, Julian Feß, and Artur Widera — Department of Physics and Research Center optimas, University of Kaiserslautern-Landau, Erwin Schrödinger Str. 46, 67663 Kaiserslautern, Germany

Diffusion is a transport phenomenon that appears as a fundamental process in almost all physical systems, ranging from subdiffusion to hyperballistic diffusion, depending on the external parameters. In addition to the properties of the bath or the diffusing particle, the diffusion in systems subjected to external forces is critical for understanding transport phenomena in complex systems.

Here, we present a system where we can observe the diffusion dynamics of single atoms in tilted optical lattices in the underdamped regime. A one-dimensional optical lattice allows transporting individual cesium atoms with variable lattice depth, constant velocity or acceleration, and thus force. For example, the force exerted on individual atoms can be huge, exceeding standard gravitation by orders of magnitude. Thereby, very different regimes of diffusion can be experimentally accessed. We can tune the system’s macroscopic diffusion coefficient by varying the lattice depth and acceleration while applying optical molasses onto the atoms as a "bath of light" for the diffusion. Additionally, the atoms can be transported through a bath of ultracold rubidium atoms. We observe the interplay of the large Rb-bath and the single Cs-atoms trapped in the accelerated lattice and report its effective friction.

Keywords: diffusion; single atoms