Probing the Efimov discrete scaling in atom-molecule collision

TL;DR

This paper demonstrates that Efimov discrete scaling behavior can be observed in atom-molecule collision cross-sections at low energies, providing a new way to detect Efimov physics in ultracold mixtures with large mass disparities.

Contribution

It reveals the Efimov discrete scaling in atom-molecule scattering cross-sections, linking three-body physics to measurable low-energy collision data in mass-imbalanced systems.

Findings

Efimov scaling appears in atom-molecule elastic cross-sections.

Zeros/minima in cross-section follow Efimov geometrical law.

Potential for experimental detection in ultracold mixtures.

Abstract

The discrete Efimov scaling behavior, well-known in the low-energy spectrum of three-body bound systems for large scattering lengths (unitary limit), is identified in the energy dependence of atom-molecule elastic cross-section in mass imbalanced systems. That happens in the collision of a heavy atom with mass $m_H$ with a weakly-bound dimer formed by the heavy atom and a lighter one with mass $m_L \ll m_H$. Approaching the heavy-light unitary limit the $s-$wave elastic cross-section $\sigma$ will present a sequence of zeros/minima at collision energies following closely the Efimov geometrical law. Our results open a new perspective to detect the discrete scaling behavior from low-energy scattering data, which is timely in view of the ongoing experiments with ultra-cold binary mixtures having strong mass asymmetries, such as Lithium and Caesium or Lithium and Ytterbium.