Three bodies bind even when two do not: Efimov states and Fano resonances in atoms and nuclei

TL;DR

This paper discusses the recent experimental confirmation of Efimov states, three-body bound states that occur even when two-body interactions do not support binding, with applications in atomic and nuclear physics.

Contribution

It provides a pedagogical overview of Efimov states and reports recent experimental evidence in cold atoms and neutron-rich nuclei confirming their existence.

Findings

First clear evidence of Efimov states in cold cesium atoms.

Observation of Efimov states in neutron-rich nuclei.

Confirmation of theoretical predictions from decades ago.

Abstract

Efimov's prediction more than three decades ago that three-body bound states can exist when the pairwise attractions do not bind or only support weakly bound states of a pair, has remained unconfirmed till just the past year. This lecture provides the pedagogical background for recent work on Efimov states in neutron-rich nuclei done with I. Mazumdar (TIFR) and V. S. Bhasin (Delhi University), and published in Phys. Rev. Lett. 97, 062503 (2006). Both these nuclear systems and recent observations of cold cesium atoms provide the first clear evidence for the existence of Efimov states.