Faserteststrecken-Workshop

Am 12./13.09. veranstaltet QR.X einen technischen Workshop zur Implementierung von Faserteststrecken für die Quantenkommunikation. Der Workshop soll dem Erfahrungsaustausch und dem Know-how-Transfer innerhalb des Projektverbundes dienen. Oberstes Ziel ist es, dass wir voneinander lernen, wie man Faserteststrecken implementiert und für Experimente in der Quantenkommunikation / Quantenrepeater nutzt. (Themen u.a. Layout/Topologie von Faserteststrecken;…

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Statistical limits for quantum networks with semiconductor entangled photon sources

Semiconductor quantum dots are promising building blocks for quantum communication applications. Although deterministic, efficient, and coherent emission of entangled photons has been realized, implementing a practical quantum repeater remains outstanding. Here we explore the statistical limits for entanglement swapping with sources of polarization-entangled photons from the commonly used biexciton-exciton cascade….

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Entangling a Hole Spin with a Time-Bin Photon: A Waveguide Approach for Quantum Dot Sources of Multi-Photon Entanglement

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…

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On-chip spin-photon entanglement based on single-photon scattering

The realization of on-chip quantum gates between photons and solid-state spins is a key building block for quantum-information processors, enabling, e.g., distributed quantum computing, where remote quantum registers are interconnected by flying photons. Self-assembled quantum dots integrated in nanostructures are one of the most promising systems for such an endeavor…

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Quantum Interference of Identical Photons from Remote Quantum Dots

Photonic quantum technology provides a viable route to quantum communication, quantum simulation, and quantum information processing. Recent progress has seen the realisation of boson sampling using 20 single-photons and quantum key distribution over hundreds of kilometres. Scaling the complexity requires photonic architectures containing a large number of single photons, multiple…

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Anonymous conference key agreement in linear quantum networks

Sharing multi-partite quantum entanglement between parties allows for diverse secure communication tasks to be performed. Among them, conference key agreement (CKA), an extension of key distribution to multiple parties, has received much attention recently. Interestingly, CKA can also be performed in a way that protects the identities of the participating…

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QR.X Statusseminar 2022

Am 02.06 und 03.06.2022 findet das erste Statusseminar von QR.X im Physikzentrum Bad Honnef statt. Nebst Vorträgen und Postern, in denen der aktuelle Stand der Bemühungen des QR.X-Konsortiums vorgestellt wird, konnte David Gershoni (Technion, Israel) gewonnen werden seine Forschungsbemühungen zu photonischen Clusterzuständen vorzustellen. Darüber hinaus wird sich in einer Fokussession…

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All-optical Tuning of Indistinguishable Single-Photons Generated in Three-level Quantum Systems

Resonance fluorescence of two-level quantum systems has emerged as a powerful tool in quantum information processing. Extension of this approach to higher-level systems provides new opportunities for quantum optics applications. Here we introduce an all-optical tuning functionality into a well-established resonance fluorescence coherent driving scheme. We accomplish this by resonant…

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