Interferometry of Efimov states in thermal gases by modulated magnetic fields

TL;DR

This paper introduces a magnetic field pulse interferometer to measure Efimov trimer energies and lifetimes in thermal gases, revealing interference patterns despite thermal effects and providing insights into trimer damping times.

Contribution

The study presents a novel interferometry method using modulated magnetic fields to analyze Efimov states in thermal gases, independent of interaction sign and magnitude.

Findings

Interference fringes observed in thermal gases despite thermal effects.

Distinct damping timescales linked to Efimov trimer lifetimes.

Interpretation of large damping timescales in previous experiments.

Abstract

We demonstrate that an interferometer based on modulated magnetic field pulses enables precise characterization of the energies and lifetimes of Efimov trimers irrespective of the magnitude and sign of the interactions in 85Rb thermal gases. Despite thermal effects, interference fringes develop when the dark time between the pulses is varied. This enables the selective excitation of coherent superpositions of trimer, dimer and free atom states. The interference patterns possess two distinct damping timescales at short and long dark times that are either equal to or twice as long as the lifetime of Efimov trimers, respectively. Specifically, this behavior at long dark times provides an interpretation of the unusually large damping timescales reported in a recent experiment with 7Li thermal gases [Phys. Rev. Lett. 122, 200402 (2019)]. Apart from that, our results constitute a stepping stone towards a high precision few-body state interferometry for dense quantum gases.