# Observation of Efimov molecules created from a resonantly interacting Bose gas

## TL;DR

This study demonstrates the creation of Efimov trimers from a resonantly interacting Bose gas and analyzes their decay dynamics, revealing their presence alongside Feshbach dimers and their stability properties.

## Contribution

The paper provides experimental evidence of Efimov molecules in a Bose gas and characterizes their decay behavior and formation efficiency, advancing understanding of few-body quantum states.

## Key findings

- Approximately 8% of atoms form Efimov trimers.
- Efimov trimers have a density-independent lifetime of about 100 μs.
- Feshbach dimer lifetime depends on density due to inelastic collisions.

## Abstract

We convert a strongly interacting ultracold Bose gas into a mixture of atoms and molecules by sweeping the interactions from resonant to weak. By analyzing the decay dynamics of the molecular gas, we show that in addition to Feshbach dimers it contains Efimov trimers. Typically around 8\% of the total atomic population is bound into trimers, identified by their density-independent lifetime of about 100~$\mu$s. The lifetime of the Feshbach dimers shows a density dependence due to inelastic atom-dimer collisions, in agreement with theoretical calculations. We also vary the density of the gas across a factor of 250 and investigate the corresponding atom loss rate at the interaction resonance.