Measurement of the Angular Dependence of the Dipole-Dipole Interaction Between Two Individual Rydberg Atoms at a F\"orster Resonance

TL;DR

This study measures how the dipole-dipole interaction between two Rydberg atoms varies with angle, demonstrating control over interaction channels at a F"orster resonance for potential quantum applications.

Contribution

The paper presents the first direct measurement of the angular dependence of Rydberg atom interactions at a F"orster resonance with controlled relative positions.

Findings

Interaction strength follows the expected angular dependence $propto(1-3\cos^2 heta)$

Controlled isolation of a single interaction channel achieved

Results align well with theoretical predictions

Abstract

We measure the angular dependence of the resonant dipole-dipole interaction between two individual Rydberg atoms with controlled relative positions. By applying a combination of static electric and magnetic fields on the atoms, we demonstrate the possibility to isolate a single interaction channel at a F\"orster resonance, that shows a well-defined angular dependence. We first identify spectroscopically the F\"orster resonance of choice and we then perform a direct measurement of the interaction strength between the two atoms as a function of the angle between the internuclear axis and the quantization axis. Our results show good agreement with the expected angular dependence $\propto(1-3\cos^2\theta)$, and represent an important step towards quantum state engineering in two-dimensional arrays of individual Rydberg atoms.