Microscopic origin and universality classes of the Efimov three-body parameter

Area of Science:

• * Quantum mechanics
• * Few-body physics

Background:

• * The low-energy spectrum of three interacting particles is governed by the three-body parameter.
• * This parameter is particularly important in the Efimov regime, characterized by nearly resonant two-body interactions.

Purpose of the Study:

• * To investigate the relationship between the three-body parameter and zero-energy two-body correlations.
• * To identify classes of two-body interactions yielding universal three-body parameter values.

Main Methods:

• * Theoretical analysis of low-energy three-particle interactions.
• * Examination of zero-energy two-body correlations.

Main Results:

• * The three-body parameter is fundamentally determined by the zero-energy two-body correlation.
• * Two distinct classes of two-body interactions exhibit a universal three-body parameter, scaled by their effective range.
• * One class aligns with universality observed in ultracold atomic systems.
• * The second class is pertinent to short-range interactions in nuclear and condensed matter physics.

Conclusions:

• * The zero-energy two-body correlation provides a universal description of the three-body parameter.
• * This finding unifies understanding across different physical systems, from ultracold atoms to nuclear and solid-state physics.