Universal three-body parameter in ultracold 4He*

TL;DR

This study demonstrates that the three-body parameter in ultracold 4He atoms aligns with those found in alkali-metal experiments, supporting the universality of Efimov physics beyond alkali metals.

Contribution

It provides the first evidence of a universal three-body parameter in a non-alkali atomic system, specifically in ultracold 4He, based on experimental analysis.

Findings

Three-body loss rate coefficient consistent with universal 3BP

Supports universality of Efimov physics beyond alkali metals

Suggests other atomic systems with large scattering lengths are promising for further study

Abstract

We have analyzed our recently-measured three-body loss rate coefficient for a Bose-Einstein condensate of spin-polarized metastable triplet 4He atoms in terms of Efimov physics. The large value of the scattering length for these atoms, which provides access to the Efimov regime, arises from a nearby potential resonance. We find the loss coefficient to be consistent with the three-body parameter (3BP) found in alkali-metal experiments, where Feshbach resonances are used to tune the interaction. This provides new evidence for a universal 3BP, the first outside the group of alkali-metal elements. In addition, we give examples of other atomic systems without Feshbach resonances but with a large scattering length that would be interesting to analyze once precise measurements of three-body loss are available.