14 research outputs found
High-fidelity multi-photon-entangled cluster state with solid-state quantum emitters in photonic nanostructures
We propose a complete architecture for deterministic generation of entangled
multiphoton states. Our approach utilizes periodic driving of a quantum-dot
emitter and an efficient light-matter interface enabled by a photonic crystal
waveguide. We assess the quality of the photonic states produced from a real
system by including all intrinsic experimental imperfections. Importantly, the
protocol is robust against the nuclear spin bath dynamics due to a naturally
built-in refocussing method reminiscent to spin echo. We demonstrate the
feasibility of producing Greenberger-Horne-Zeilinger and one-dimensional
cluster states with fidelities and generation rates exceeding those achieved
with conventional 'fusion' methods in current state-of-the-art experiments. The
proposed hardware constitutes a scalable and resource-efficient approach
towards implementation of measurement-based quantum communication and
computing
Quantum Key Distribution using Deterministic Single-Photon Sources over a Field-Installed Fibre Link
Quantum-dot-based single-photon sources are key assets for quantum
information technology, supplying on-demand scalable quantum resources for
computing and communication. However, longlasting issues such as limited
long-term stability and source brightness have traditionally impeded their
adoption in real-world applications. Here, we realize a quantum key
distribution field trial using true single photons across an 18-km-long dark
fibre, located in the Copenhagen metropolitan area, using an optimized,
state-of-the-art, quantum-dot single-photon source frequency-converted to the
telecom wavelength. A secret key generation rate of 2 kbits/s realized over a
9.6 dB channel loss is achieved with a polarization-encoded BB84 scheme,
showing remarkable stability for more than 24 hours of continuous operation.
Our results highlight the maturity of deterministic single-photon source
technology while paving the way for advanced single-photon-based communication
protocols, including fully device-independent quantum key distribution, towards
the goal of a quantum internet.Comment: 9 pages, 4 figure
Dissolving the dichotomies between online and campus-based teaching: a collective response to The manifesto for teaching online (Bayne et al. 2020)
This article is a collective response to the 2020 iteration of The Manifesto for Teaching Online. Originally published in 2011 as 20 simple but provocative statements, the aim was, and continues to be, to critically challenge the normalization of education as techno-corporate enterprise and the failure to properly account for digital methods in teaching in Higher Education. The 2020 Manifesto continues in the same critically provocative fashion, and, as the response collected here demonstrates, its publication could not be timelier. Though the Manifesto was written before the Covid-19 pandemic, many of the responses gathered here inevitably reflect on the experiences of moving to digital, distant, online teaching under unprecedented conditions. As these contributions reveal, the challenges were many and varied, ranging from the positive, breakthrough opportunities that digital learning offered to many students, including the disabled, to the problematic, such as poor digital networks and access, and simple digital poverty. Regardless of the nature of each response, taken together, what they show is that The Manifesto for Teaching Online offers welcome insights into and practical advice on how to teach online, and creatively confront the supremacy of face-to-face teaching
The Business of Making Games : Guidelines and questions to get you thinking about your game studio's business strategy.
This report is the result of the Scandinavian Game Developers (SGD) project and a distillation of experience acquired from working with the several involved incubation environments, such as the Ranch in Grenaa, the Arsenal in Viborg and Gothia Science Park in Skövde. While most other publications from the SGD project have been academic in nature, this material has been written to be more practically oriented and directly applicable in game development studios. It is the hope of the authors that this report will allow young start-up companies within the game business of Scandinavia to structure their thoughts and business plans more thoroughly. While there are precious few answers to give to the question of how you succeed in the games business, there are a series of productive questions to be asked. We hope that this report will help you ask the right questions in the right combination.Scandinavian Game Developer
Fidelity of time-bin entangled multi-photon states from a quantum emitter
We devise a mathematical framework for assessing the fidelity of multi-photon
entangled states generated by a single solid-state quantum emitter, such as a
quantum dot or a nitrogen-vacancy center. Within this formalism, we
theoretically study the role of imperfections present in real systems on the
generation of time-bin encoded Greenberger-Horne-Zeilinger and one-dimensional
cluster states. We consider both fundamental limitations, such as the effect of
phonon-induced dephasing, interaction with the nuclear spin bath, and
second-order emissions, as well as technological imperfections, such as
branching effects, non-perfect filtering, and photon losses. In a companion
paper, we consider a particular physical implementation based on a quantum dot
emitter embedded in a photonic crystal waveguide and apply our theoretical
formalism to assess the fidelities achievable with current technologies