Non-Markovian decoherence of localized nanotube excitons by acoustic phonons

TL;DR

This paper investigates how electron-phonon interactions cause non-Markovian decoherence in localized nanotube excitons, revealing significant pure-dephasing effects that impact quantum information applications.

Contribution

It provides a detailed experimental and theoretical analysis of phonon-induced decoherence in one-dimensional nanotube excitons using the independent boson model.

Findings

Phonon interactions cause broad, asymmetric emission lines.

Pure-dephasing exceeds lifetime broadening by two orders of magnitude.

Non-Markovian decoherence may hinder quantum information processing.

Abstract

We demonstrate that electron-phonon interaction in quantum dots embedded in one-dimensional systems leads to pronounced, non-Markovian decoherence of optical transitions. The experiments we present focus on the lineshape of photoluminescence from low-temperature axially localized carbon nanotube excitons. The independent boson model that we use to model the phonon interactions reproduces with very high accuracy the broad and asymmetric emission lines and the weak red-detuned radial breathing mode replicas observed in the experiments. The intrinsic phonon-induced pure-dephasing of the zero-phonon line is two orders of magnitude larger than the lifetime broadening and is a hallmark of the reduced dimensionality of the phonon bath. The non-Markovian nature of this decoherence mechanism may have adverse consequences for applications of one-dimensional systems in quantum information processing.