Photon-Mediated Spin-Exchange Dynamics of Spin-1 Atoms

TL;DR

This paper demonstrates photon-mediated long-range spin-exchange interactions in cold rubidium atoms within an optical resonator, enabling control over interaction properties and observing correlated pair creation, advancing quantum simulation and metrology.

Contribution

It provides the first direct observation and control of photon-mediated spin-exchange interactions in a cold atom ensemble, including the creation of correlated pairs in a spin-1 system.

Findings

Interactions extend over 500 microns.

Optical control of interaction strength and sign.

Observation of correlated pair creation in spin states.

Abstract

We report direct observations of photon-mediated spin-exchange interactions in an atomic ensemble. Interactions extending over a distance of 500 microns are generated within a cloud of cold rubidium atoms coupled to a single mode of light in an optical resonator. We characterize the system via quench dynamics and imaging of the local magnetization, verifying the coherence of the interactions and demonstrating optical control of their strength and sign. Furthermore, by initializing the spin-1 system in the mF = 0 Zeeman state, we observe correlated pair creation in the mF = +/- 1 states, a process analogous to spontaneous parametric down-conversion and to spin mixing in Bose-Einstein condensates. Our work opens new opportunities in quantum simulation with long-range interactions and in entanglement-enhanced metrology.