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

Area of Science:

• Atomic physics
• Quantum mechanics
• Few-body systems

Background:

• The lithium few-body puzzle highlights a discrepancy between theoretical predictions and experimental observations of the three-body spectrum.
• Previous models failed to account for the observed Efimovian spectrum in lithium-7 ($^{7}$Li).

Purpose of the Study:

• To resolve the long-standing disagreement between theory and experiment in the Efimovian three-body spectrum of $^{7}$Li.
• To identify the underlying physical mechanisms responsible for the observed discrepancy.

Main Methods:

• Numerical solution of the quantum mechanical three-body problem.
• Inclusion of precise interatomic interactions and all spin degrees of freedom for three alkali-metal atoms.
• Analysis of three-body recombination rates and reaction propensities.

Main Results:

• Identified strong nonuniversal three-body spin-exchange interactions as the cause of the discrepancy.
• Demonstrated that these interactions effectively inflate the universal Efimov spectrum.
• Achieved excellent agreement with experimental data for both the Efimov spectrum and three-body recombination rate constants.

Conclusions:

• The lithium few-body puzzle is resolved by incorporating spin-exchange interactions.
• The study reveals a general product propensity for triatomic reactions in the Paschen-Back regime, consistent with Wigner's spin conservation rule.
• Provides a comprehensive understanding of three-body interactions in alkali-metal systems.