Entanglement transfer from electrons to photons in quantum dots: An open quantum system approach

TL;DR

This paper explores how entanglement from spin-entangled electron-hole pairs in quantum dots can be transferred to emitted photons, using an open quantum system approach to analyze environmental effects and measurement schemes.

Contribution

It introduces a detailed model of entanglement transfer in quantum dots, considering realistic measurement and dephasing effects, and proposes methods to verify photon entanglement.

Findings

Photon entanglement can be achieved via electron spin entanglement in quantum dots.

Environmental interactions and asymmetries affect the degree of photon entanglement.

Verification schemes based on CHSH inequality and interference fringes are effective.

Abstract

We investigate entanglement transfer from a system of two spin-entangled electron-hole pairs, each placed in a separate single mode cavity, to the photons emitted during their recombination process. Dipole selection rules and a splitting between the light-hole and the heavy-hole subbands are the crucial ingredients establishing a one-to-one correspondence between electron spins and circular photon polarizations. To account for the measurement of the photons as well as dephasing effects, we choose a stochastic Schroedinger equation and a conditional master equation approach, respectively. The influence of interactions with the environment as well as asymmetries in the coherent couplings on the photon-entanglement is analyzed for two concrete measurement schemes. The first one is designed to violate the Clauser-Horne-Shimony-Holt (CHSH) inequality, while the second one employs the visibility of interference fringes to prove the entanglement of the photons. Because of the spatial separation of the entangled electronic system over two quantum dots, a successful verification of entangled photons emitted by this system would imply the detection of nonlocal spin-entanglement of massive particles in a solid state structure.