Experimental realization of a Rydberg optical Feshbach resonance in a quantum many-body system

O Thomas,H Ott,C Lippe,T Eichert

doi:10.1038/s41467-018-04684-w

Abstract

Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas. The commonly used magnetic Feshbach resonances are specific for each species and are restricted with respect to their temporal and spatial modulation. Optical Feshbach resonances are an alternative which can overcome this limitation. Here, we show that ultra-long-range Rydberg molecules can be used to implement an optical Feshbach resonance. Tuning the on-site interaction of a degenerate Bose gas in a 3D optical lattice, we demonstrate a similar performance compared to recent realizations of optical Feshbach resonances using intercombination transitions. Our results open up a class of optical Feshbach resonances with a plenitude of available lines for many atomic species and the possibility to further increase the performance by carefully selecting the underlying Rydberg state.

Highlights

Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas
An alternative approach is provided by purely optical Feshbach resonances (OFRs)[7], which use a light field to couple a colliding atomic pair to a bound molecular state
In this work we investigate 87Rb atoms colliding in the 3Σu ground-state potential which is optically coupled to the vibrational ground state of a molecular state at a bond length of ≈700a0 (Bohr radius) of the so-called deep ultra-long-range Rydberg molecule potential, which adiabatically connects to the 25P3=2; F 1⁄4 2 state

Summary

Introduction

Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas. In an OFR, the two incoming atoms (open channel) are coupled to a bound molecular state (closed channel) by a laser field This causes a distortion of the wave function leading to a change in the scattering length and a change in the interaction of the two atoms. One peculiarity of a Rydberg OFR is the separation of length scales: the interatomic distance at which the molecule is formed exceeds by far the short-range molecular potential of two ground-state atoms. The details of the experimental setup can be found in ref. 17 and a description of the experimental sequence is given in the methods

Methods

Results

Conclusion