# Visualizing Efimov Correlations in the Bose Polaron

## TL;DR

This paper demonstrates that a large mass imbalance in Bose polaron systems can reveal Efimov physics signatures in spectroscopic measurements, using a diagrammatic Virial expansion approach.

## Contribution

It introduces a novel method to detect Efimov correlations in Bose polarons by leveraging mass imbalance and diagrammatic analysis.

## Key findings

- Identification of two Efimov branches in the polaron spectrum.
- Observation of hybridization between Efimov states and the attractive polaron.
- Proposal of experimental conditions to observe Efimov physics signatures.

## Abstract

The Bose polaron is a quasi-particle of an impurity dressed by surrounding bosons. In few-body physics, it is known that two identical bosons and a third distinguishable particle can form a sequence of Efimov bound states in the vicinity of inter-species scattering resonance. On the other hand, in the Bose polaron system with an impurity atom embedded in many bosons, no signature of Efimov physics has been reported in the existing spectroscopy measurements up to date. In this work, we propose that a large mass imbalance between a light impurity and heavy bosons can help produce visible signatures of Efimov physics in such a spectroscopy measurement. Using the diagrammatic approach in the Virial expansion to include three-body effects from pair-wise interactions, we determine the impurity self-energy and its spectral function. Taking $^{6}$Li-$^{133}$Cs\ system as a concrete example, we find two visible Efimov branches in the polaron spectrum, as well as their hybridizations with the attractive polaron branch. We also discuss the general scenarios for observing the signature of Efimov physics in polaron systems. This work paves the way for experimentally exploring intriguing few-body correlations in a many-body system in the near future.