Emergent Inflation of the Efimov Spectrum under Three-Body Spin-Exchange Interactions

We resolve the unexpected and long-standing disagreement between experiment and theory in the Efimovian three -body spectrum of 7Li, commonly referred to as the lithium few -body puzzle. Our results show that the discrepancy arises out of the presence of strong nonuniversal 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.