Quantum-enabled active matter at the atomic scale

arXiv (Cornell University)

Abstract

Active matter comprises particles that extract energy from their local environment and convert it into motion. Although active particles have been miniaturized down to the nanoscale, realizing activity at the fundamentally smaller scale of individual atoms remains an open challenge, where quantum effects become increasingly relevant. Here, we experimentally demonstrate that individual Cs-133 atoms confined in an optical dipole trap extract energy from an ultracold bath of Rb-87 atoms via quantum-mechanical spin interactions and convert it into active motion. We quantitatively reproduce the resulting dynamics using a parameter-free active Langevin model derived from kinetic theory and support it with event-driven Monte Carlo collision simulations. The microscopic origin of activity is identified as quantum spin exchange, which transfers discrete internal spin energy into kinetic motion. Our work establishes a quantum-enabled route to active matter at the fundamental size limit of single atoms and opens perspectives for exploring the interplay of activity, quantum physics, and mesoscopic non-equilibrium thermodynamics.

Authors 11

1. Sabrina Burgardt

   University of Kaiserslautern

   Affiliation as printed

   Department of Physics and State Research Center OPTIMAS , RPTU University Kaiserslautern -Landau , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany

2. Julian Feß

   University of Kaiserslautern

   Affiliation as printed

   Department of Physics and State Research Center OPTIMAS , RPTU University Kaiserslautern -Landau , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany

3. Alexander Guthmann

   University of Kaiserslautern

   Affiliation as printed

   Department of Physics and State Research Center OPTIMAS , RPTU University Kaiserslautern -Landau , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany

4. Silvia Hiebel

   University of Kaiserslautern

   Affiliation as printed

   Department of Physics and State Research Center OPTIMAS , RPTU University Kaiserslautern -Landau , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany

5. Aritra K. Mukhopadhyay

   Technische Universität Darmstadt

   Affiliation as printed

   Institute for Condensed Matter Physics , Technical University of Darmstadt , Hochschulstraße 8 , 64285 Darmstadt , Germany

6. Sangyun Lee

   Johannes Gutenberg University Mainz

   Affiliation as printed

   Institute of Physics , Johannes-Gutenberg University Mainz , Staudingerweg 9 , 55128 Mainz , Germany

7. Michael te Vrugt
8. Benno Liebchen

   Technische Universität Darmstadt

   Affiliation as printed

   Institute for Condensed Matter Physics , Technical University of Darmstadt , Hochschulstraße 8 , 64285 Darmstadt , Germany

9. Hartmut Löwen

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Institute of Theoretical Physics II: Soft Matter , Heinrich-Heine University Düsseldorf , Universitätsstraße 1 , 40225 Düsseldorf , Germany

10. Raphael Wittkowski Aachen Department of Physics

    DWI – Leibniz Institute for Interactive Materials

    Affiliation as printed

    Department of Physics , RWTH Aachen University and DWI -Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , 52074 Aachen , Germany

11. Artur Widera

    University of Kaiserslautern

    Affiliation as printed

    Department of Physics and State Research Center OPTIMAS , RPTU University Kaiserslautern -Landau , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany