Can a simple model describe the collisions in Erbium spin mixtures?

POSTER

Abstract

The collisional properties of lanthanides exhibit remarkable complexity due to their strong long-ranged dipole-dipole interactions, anisotropic short-ranged interactions and complex magnetic structure, leading to an extraordinarily dense Feshbach spectrum showing signs of quantum chaos. Nevertheless, certain qualitative features of two-body collisions recently observed in spin mixtures of bosonic Erbium can be reproduced by a simple phenomenological multichannel square-well model. Unlike Feshbach resonances observed in collisions of alkali atoms, the resonance profiles observed in spin-resolved atom loss measurements exhibit a pronounced Fano asymmetry that is a result of interference between two collision pathways.  We identify a sequence of resonances that we believe to be caused by a single molecular state. Five independent model parameters are tuned to reproduce a single resonance and the resulting model is used to quantitatively predict the atom-loss profiles for six other resonances in different spin states.  We discuss the Fano asymmetry in the atom-loss profiles, as well as the observed exponential scaling of the resonance widths with respect to increasing (less negative) values of the magnetic quantum number.

*We acknowledge support from the European Research Council through the Advanced Grant DyMETEr (10.3030/101054500), a NextGeneration EU Grant AQuSIM through the Austrian Research Promotion Agency (FFG) (No. FO999896041), and the Austrian Science Fund (FWF) Cluster of Excellence QuantA (10.55776/COE1). J. J. A. H. and L. L. acknowledge funding from the Austrian Science Fund (FWF) within the DK-ALM (10.55776/W1259). L. L. acknowledges funding from a joint-project grant from the FWF (No. I-4426). N. P. M. and S. T. R. acknowledge support in part by the National Science Foundation through NSF PHY-2409110 and PHY-2409111, and also by the Kavli Institute for Theoretical Physics through NSF PHY-2309135.

Publication: Preprint: arXiv:2512.17556

Presenters

  • Nirav P Mehta

    • Department of Physics and Astronomy, Trinity University, San Antonio, USA and Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Netherlands
    • Trinity University
    • Trinity University, San Antonio TX

Authors

  • Nirav P Mehta

    • Department of Physics and Astronomy, Trinity University, San Antonio, USA and Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Netherlands
    • Trinity University
    • Trinity University, San Antonio TX

  • Seth T Rittenhouse

    • Department of Physics, the United States Naval Academy, Annapolis, USA and Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Netherlands
    • US Naval Academy

  • Louis Lafforgue

    • Universität Innsbruck

  • Sarah Embacher

    • Universität Innsbruck, Innsbruck, Austria and Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria
    • Universität Innsbruck

  • Ferdinand Claude

    • Universität Innsbruck

  • Arfor J Houwman

    • Universität Innsbruck

  • Francesca Ferlaino

    • University of Innsbruck

  • Manfred J Mark

    • Universität Innsbruck, Innsbruck, Austria and Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria
    • Universität Innsbruck