Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 70: Ultracold Atoms II (joint session Q/A)

Q 70.5: Talk

Friday, March 9, 2018, 11:30–11:45, K 1.022

Diffusion of Ultracold Atoms Coupled to tailored Bath — •Daniel Adam, Tobias Lausch, Daniel Mayer, Felix Schmidt, Quentin Bouton, and Artur Widera — TU Kaiserslautern, Department of Physics, Kaiserslautern, Germany

Diffusion is an essential phenomenon in nature, occurring in various systems from biological cells to traffic models. Ultracold atoms are ideal model systems to go beyond the mere observation of single particle diffusion, and to engineer the surrounding baths by external fields.

Here, we consider the diffusion of single neutral atoms trapped in a periodic potential and coupled to a near-resonant light field forming the bath. This bath defines both fluctuations as well as the diffusion coefficient via the laser cooling properties of the optical molasses. The diffusion coefficient significantly determines the dynamics of a diffusing tracer, thus its knowledge is of central importance to understand the fundamental diffusion. I will present a method to measure the diffusion coefficient directly with single Cs-atoms confined in a harmonic potential. This method is similar to the method of tethered particle motion known for the observation of DNA dynamics.

Precise knowledge of the diffusion coefficient as a function of external experimental parameters opens the route for quantitative measurements of diffusion in complex potential landscapes or non-equilibrium situations.