Entanglement transfer from electron spins to photons in spin light-emitting diodes containing quantum dots

TL;DR

This paper demonstrates a method to transfer entanglement from electron spins in quantum dots to photon polarizations, enabling the generation of GHZ-type entangled photon states with high fidelity using current technology.

Contribution

It introduces a novel scheme for entanglement transfer in quantum dots that is robust against fine structure splitting and spin decoherence, and details its experimental feasibility.

Findings

Efficient entanglement transfer from electron spins to photons in quantum dots.

Generation of GHZ-type four-photon entangled states.

High-fidelity entangled photon pairs achievable with current techniques.

Abstract

We show that electron recombination using positively charged excitons in single quantum dots provides an efficient method to transfer entanglement from electron spins onto photon polarizations. We propose a scheme for the production of entangled four-photon states of GHZ type. From the GHZ state, two fully entangled photons can be obtained by a measurement of two photons in the linear polarization basis, even for quantum dots with observable fine structure splitting for neutral excitons and significant exciton spin decoherence. Because of the interplay of quantum mechanical selection rules and interference, maximally entangled electron pairs are converted into maximally entangled photon pairs with unity fidelity for a continuous set of observation directions. We describe the dynamics of the conversion process using a master-equation approach and show that the implementation of our scheme is feasible with current experimental techniques.