Coherent Control of Photon Correlations in Trapped Ion Crystals

TL;DR

This paper demonstrates how the interplay of spontaneous emission and coherent scattering in trapped ion crystals can be used to control photon correlations and statistics, revealing complex spatial and statistical behaviors.

Contribution

It experimentally shows the control of photon correlations in large ion systems by combining spontaneous emission and coherent scattering effects.

Findings

Observation of anti-correlation between photon rates and variance in 18-ion chains.

Transition from sub-Poissonian to super-Poissonian photon variance in 4-ion crystals.

Strong deviation from incoherent scattering in large ion systems.

Abstract

While the spontaneous emission from independent emitters provides spatially uncorrelated photons - a typical manifestation of quantum randomness, the interference of the coherent scattering leads to a well-defined intensity pattern - a feature described by linear optics. We here demonstrate experimentally how the interplay between the two mechanisms in large systems of quantum emitters leads to spatial variations of photon correlations. The implementation with trapped ion crystals in free space allows us to observe the anti-correlation between photon rates and variance of the photon number distributions in chains of up to 18 ions. For smaller crystals of four ions, the transition from a sub-Poissonian to a super-Poissonian variance of the photon number in the scattered light is reported. For higher numbers of scatterers, the photon statistics still display a strong deviation from the fully incoherent scattering case. Our results illustrate how the interference of coherent scattering, combined with spontaneous emission, provides a control mechanism for the light statistics.