Emergent inflation of the Efimov spectrum under three-body spin-exchange interactions

TL;DR

This paper explains the long-standing discrepancy in lithium-7 Efimov spectrum measurements by identifying strong spin-exchange interactions as the cause, leading to an inflation of the spectrum and aligning theory with experiments.

Contribution

It demonstrates that non-universal three-body spin-exchange interactions cause spectrum inflation, resolving the lithium few-body puzzle through detailed quantum mechanical calculations.

Findings

Excellent agreement with experimental Efimov spectrum data

Identification of spin-exchange interactions as the inflation mechanism

Revealed a general product propensity in triatomic reactions in the Paschen-Back regime

Abstract

We resolve the unexpected and long-standing disagreement between experiment and theory in the Efimovian three-body spectrum of Li-7, commonly referred to as the lithium few-body puzzle. Our results show that the discrepancy arises out of the presence of strong non-universal three-body spin-exchange interactions, which enact an effective inflation of the universal Efimov spectrum. This conclusion is obtained from a thorough numerical solution of the quantum mechanical three-body problem, including precise interatomic interactions and all spin degrees of freedom for three alkali-metal atoms. Our results show excellent agreement with the experimental data regarding both the Efimov spectrum and the absolute rate constants of three-body recombination, and in addition reveal a general product propensity for such triatomic reactions in the Paschen-Back regime, stemming from Wigner's spin conservation rule.