Statistical Aging and Non Ergodicity in the Fluorescence of Single Nanocrystals

TL;DR

This paper investigates the fluorescence behavior of single CdSe nanocrystals, revealing statistical aging and ergodicity breaking due to Levy statistics, which impacts how ensemble and single-particle measurements are interpreted.

Contribution

It demonstrates the presence of Levy statistics, aging, and ergodicity breaking in nanocrystal fluorescence, highlighting differences between ensemble and single-particle behaviors.

Findings

Observation of Levy statistics in nanocrystal fluorescence

Detection of statistical aging and ergodicity breaking

Discrepancies between ensemble and single-particle measurements

Abstract

The relation between single particle and ensemble measurements is adressed for semiconductor CdSe nanocrystals. We record their fluorescence at the single molecule level and analyse their emission intermittency, which is governed by unusual random processes known as Levy statistics. We report the observation of statistical aging and ergodicity breaking, both related to the occurrence of Levy statistics. Our results show that the behaviour of ensemble quantities, such as the total fluorescence of an ensemble of nanocrystals, can differ from the time averaged individual quantities, and must be interpreted with care.