Observation of Stueckelberg oscillations in dipole-dipole interactions

TL;DR

This paper reports the experimental observation of Stueckelberg oscillations in dipole-dipole interactions between Rydberg atoms under RF fields, demonstrating coherent control and multi-photon transitions influenced by quadratic Stark shifts.

Contribution

It provides the first experimental demonstration of Stueckelberg oscillations in Rydberg atom interactions with detailed theoretical comparison for quadratic Stark shifts.

Findings

Observation of Stueckelberg oscillations in Rydberg atom interactions.

Coherent dipole-dipole interaction maintained for at least 0.6 microseconds.

Theoretical analysis using Floquet approach matches experimental results.

Abstract

We have observed Stueckelberg oscillations in the dipole-dipole interaction between Rydberg atoms with an externally applied radio-frequency field. The oscillating RF field brings the interaction between cold Rydberg atoms in two separated volumes into resonance. We observe multi-photon transitions when varying the amplitude of the RF-field and the static electric field offset. The angular momentum states we use show a quadratic Stark shift, which leads to a fundamentally different behavior than linearly shifting states. Both cases are studied theoretically using the Floquet approach and are compared. The amplitude of the sidebands, related to the interaction strength, is given by the Bessel function in the linearly shifting case and by the generalized Bessel function in the quadratically shifting case. The oscillatory behavior of both functions corresponds to Stueckelberg oscillations, an interference effect described by the semi-classical Landau-Zener-Stueckelberg model. The measurements prove coherent dipole-dipole interaction during at least 0.6 micro-seconds.