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Individual Tracer Atoms in an Ultracold Dilute Gas

Michael Hohmann, Farina Kindermann, Tobias Lausch, Daniel Mayer, Felix Schmidt, Eric Lutz, and Artur Widera
Phys. Rev. Lett. 118, 263401 – Published 30 June 2017
Physics logo See Focus story: Observing Diffusion Atom by Atom
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Abstract

We report on the experimental investigation of individual Cs atoms impinging on a dilute cloud of ultracold Rb atoms with variable density. We study the relaxation of the initial nonthermal state and detect the effect of single collisions which has so far eluded observation. We show that, after few collisions, the measured spatial distribution of the tracer atoms is correctly described by a Langevin equation with a velocity-dependent friction coefficient, over a large range of Knudsen numbers. Our results extend the simple and effective Langevin treatment to the realm of light particles in dilute gases. The experimental technique developed opens up the microscopic exploration of a novel regime of diffusion at the level of individual collisions.

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  • Received 23 February 2017

DOI:https://doi.org/10.1103/PhysRevLett.118.263401

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Atomic, Molecular & OpticalFluid Dynamics

Focus

Key Image

Observing Diffusion Atom by Atom

Published 30 June 2017

The tracking of individual atoms diffusing in a cold, rarefied gas reveals the influence that a single impact has on randomizing the motion.

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Authors & Affiliations

Michael Hohmann1, Farina Kindermann1, Tobias Lausch1, Daniel Mayer1,2, Felix Schmidt1,2, Eric Lutz3, and Artur Widera1,2,*

  • 1Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
  • 2Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany
  • 3Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany

  • *widera@physik.uni-kl.de

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Issue

Vol. 118, Iss. 26 — 30 June 2017

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