Higher-Order Photon Statistics as a New Tool to Reveal Hidden Excited States in a Plasmonic Cavity

TL;DR

This paper introduces a new method using higher-order factorial cumulants to analyze photon correlations, revealing hidden excited states in a plasmonic cavity with improved sensitivity and robustness.

Contribution

The authors develop a novel procedure based on factorial cumulants to evaluate photon correlation functions, enhancing detection of hidden states in quantum optical systems.

Findings

Enhanced sensitivity to photon correlations.

Detection of additional excited quantum dot states.

Robustness against limited experimental resolution.

Abstract

Among the best known quantities obtainable from photon correlation measurements are the $g^{(m)}$~correlation functions. Here, we introduce a new procedure to evaluate these correlation functions based on higher-order factorial cumulants $C_{\text{F},m}$ which integrate over the time dependence of the correlation functions, i.e., summarize the available information at different time spans. In a systematic manner, the information content of higher-order correlation functions as well as the distribution of photon waiting times is taken into account. Our procedure greatly enhances the sensitivity for probing correlations and, moreover, is robust against a limited counting efficiency and time resolution in experiment. It can be applied even in case $g^{(m)}$ is not accessible at short time spans. We use the new evaluation scheme to analyze the photon emission of a plasmonic cavity coupled to a single quantum dot. We derive criteria which must hold if the system can be described by a generic Jaynes-Cummings model. A violation of the criteria can be explained by the presence of an additional excited quantum dot state.