Quantum dot technology for quantum repeaters: from entangled photon generation towards the integration with quantum memories

TL;DR

This paper reviews the development of semiconductor quantum dots for quantum repeaters, focusing on entangled photon generation, integration with quantum memories, and recent experimental progress towards practical quantum networks.

Contribution

It provides a comprehensive overview of quantum dot technology advancements, integration strategies with quantum memories, and recent experimental implementations for quantum communication.

Findings

High entanglement fidelity achieved in GaAs quantum dots

Progress in on-demand entangled photon pair generation

Recent demonstrations of quantum communication protocols

Abstract

The realization of a functional quantum repeater is one of the major research goals in long-distance quantum communication. Among the different approaches that are being followed, the one relying on quantum memories interfaced with deterministic quantum emitters is considered as among one of the most promising solutions. In this work, we focus on memory-based quantum-repeater schemes that rely on semiconductor quantum dots for the generation of polarization entangled photons. Going through the most relevant figures of merit related to efficiency of the photon source, we select significant developments in fabrication, processing and tuning techniques aimed at combining high degree of entanglement with on-demand pair generation, with a special focus on the progress achieved in the representative case of the GaAs system. We proceed to offer a perspective on integration with quantum memories, both highlighting preliminary works on natural-artificial atomic interfaces and commenting a wide choice of currently available and potentially viable memory solutions in terms of wavelength, bandwidth and noise-requirements. To complete the overview, we also present recent implementations of entanglement-based quantum communication protocols with quantum dots and highlight the next challenges ahead for the implementation of practical quantum networks.