Topological origin of universal few-body clusters in Efimov physics

TL;DR

This paper reveals that the universal hierarchy of Efimov trimers and tetramers originates from topological properties of the renormalization-group limit cycle, indicating a topological phase transition in few-body systems.

Contribution

It identifies the topological origin of the universal few-body clusters in Efimov physics through winding numbers of the RG limit cycle.

Findings

Universal 3- and 4-body states linked to winding numbers

Topological phase transition suggested in mass-imbalanced systems

Hierarchy of clusters has a topological origin

Abstract

Efimov physics is renowned for the self-similar spectrum featuring the universal ratio of one eigenenergy to its neighbor. Even more esoteric is the numerically unveiled fact that every Efimov trimer is accompanied by a pair of tetramers. Here we demonstrate that this hierarchy of universal few-body clusters has a topological origin by identifying the numbers of universal 3- and 4-body bound states with the winding numbers of the renormalization-group limit cycle in theory space. The finding suggests a topological phase transition in mass-imbalanced few-body systems which should be tested experimentally.