Deterministic sources of multi-photon entanglement are highly attractive for quantum information processing but are challenging to realize experimentally. In this paper, we demonstrate a route towards a scaleable source of time-bin encoded Greenberger-Horne-Zeilinger and linear cluster states from a solid-state quantum dot embedded in a nanophotonic crystal waveguide. By utilizing a self-stabilizing double-pass interferometer, we measure a spin-photon Bell state with (67.8±0.4)% fidelity and devise steps for significant further improvements. By employing strict resonant excitation, we demonstrate a photon indistinguishability of (95.7±0.8)%, which is conducive to fusion of multiple cluster states for scaling up the technology and producing more general graph states.
@article{arxiv.2111.12523,
title = {Entangling a Hole Spin with a Time-Bin Photon: A Waveguide Approach for Quantum Dot Sources of Multi-Photon Entanglement},
author = {Martin Hayhurst Appel and Alexey Tiranov and Simon Pabst and Ming Lai Chan and Christian Starup and Ying Wang and Leonardo Midolo and Konstantin Tiurev and Sven Scholz and Andreas D. Wieck and Arne Ludwig and Anders Søndberg Sørensen and Peter Lodahl},
journal= {arXiv preprint arXiv:2111.12523},
year = {2022}
}