Phonon-assisted decoherence in the production of polarization-entangled photons in a single semiconductor quantum dot

TL;DR

This paper models how phonon interactions in semiconductor quantum dots cause decoherence, reducing the quality of polarization-entangled photon pairs generated via biexciton decay, highlighting a key challenge for quantum photonic devices.

Contribution

It introduces a theoretical framework to analyze phonon-assisted decoherence effects on entangled photon production in quantum dots, emphasizing boundary scattering impacts.

Findings

Phonons significantly reduce entanglement fidelity.

Boundary scattering of phonons enhances decoherence effects.

Decoherence poses a serious limitation for quantum-dot entangled-photon sources.

Abstract

We theoretically investigate the production of polarization-entangled photons through the biexciton cascade decay in a single semiconductor quantum dot. In the intermediate state the entanglement is encoded in the polarizations of the first emitted photon and the exciton, where the exciton state can be effectively ``measured'' by the solid state environment through the formation of a lattice distortion. We show that the resulting loss of entanglement becomes drastically enhanced if the phonons contributing to the lattice distortion are subject to elastic scatterings at the device boundaries, which might constitute a serious limitation for quantum-dot based entangled-photon devices.