AMO In the literature: partially resolved

Is a separate four-body parameter needed for Efimov-linked tetramers?

In plain words

Four atoms can also bind into states attached to each Efimov molecule. The question is whether their positions follow from the three-atom number alone, or need extra information.

Precise statement

Zero-range theory predicts tetramer loss resonances at a_4,1 ~ 0.43 a_- and a_4,2 ~ 0.90 a_- (von Stecher, D'Incao, Greene 2009). With realistic van der Waals interactions, determine whether these ratios are universal to 5% or depend on short-range four-body physics. Answer: yes or no with a computed and measured spread across species.

What would settle it

Precision four-body loss spectroscopy in several species with a matching van der Waals four-body calculation.

Status in the literature

Cesium experiments since 2009 roughly match the zero-range ratios, but precision tests across species are missing.

See also