Liberating Efimov physics from three dimensions

TL;DR

This paper explores how Efimov physics, traditionally confined to three dimensions, can be realized in mixed and lower-dimensional systems, revealing new phenomena and expanding the scope of universal few-body physics.

Contribution

It demonstrates the extension of Efimov physics beyond three dimensions through mixed and lower-dimensional interactions, introducing new phenomena and experimental possibilities.

Findings

Confinement-induced Efimov effect observed in mixed dimensions

Bose-Fermi crossover in Efimov spectrum identified

Formation of interlayer Efimov trimers in novel systems

Abstract

When two particles attract via a resonant short-range interaction, three particles always form an infinite tower of bound states characterized by a discrete scaling symmetry. It has been considered that this Efimov effect exists only in three dimensions. Here we review how the Efimov physics can be liberated from three dimensions by considering two-body and three-body interactions in mixed dimensions and four-body interaction in one dimension. In such new systems, intriguing phenomena appear, such as confinement-induced Efimov effect, Bose-Fermi crossover in Efimov spectrum, and formation of interlayer Efimov trimers. Some of them are observable in ultracold atom experiments and we believe that this study significantly broadens our horizons of universal Efimov physics.