Resonant Control of Interaction Between Different Electronic States

TL;DR

This paper reports the observation of a magnetic Feshbach resonance in ytterbium atoms, enabling tunable interactions between different electronic states, which is significant for quantum simulation and control.

Contribution

It demonstrates the first observation of a Feshbach resonance in two-electron ytterbium atoms and introduces a method to control interactions via anisotropic inter-atomic forces.

Findings

Feshbach resonance observed at ~1.1 G and 360 mG for different Yb isotopes.

Interaction strength varies widely near the resonance.

Resonance is induced by anisotropic inter-atomic interaction.

Abstract

We observe a magnetic Feshbach resonance in a collision between the ground and metastable states of two-electron atoms of ytterbium (Yb). We measure the on-site interaction of doubly-occupied sites of an atomic Mott insulator state in a three-dimensional optical lattice as a collisional frequency shift in a high-resolution laser spectroscopy. The observed spectra are well fitted by a simple theoretical formula, in which two particles with an s-wave contact interaction are confined in a harmonic trap. This analysis reveals a wide variation of the interaction with a resonance behavior around a magnetic field of about 1.1 Gauss for the energetically lowest magnetic sublevel of ${}^{170}$Yb, as well as around 360 mG for the energetically highest magnetic sublevel of ${}^{174}$Yb. The observed Feshbach resonance can only be induced by an anisotropic inter-atomic interaction. This novel scheme will open the door to a variety of study using two-electron atoms with tunable interaction.