Quantum Communication and Quantum Networking

Quantum Communication and Quantum Networking
Author: Alexander Sergienko
Publisher: Springer Science & Business Media
Total Pages: 324
Release: 2010-02-08
Genre: Computers
ISBN: 3642117309

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This book constitutes the proceedings of the First International Conference on Quantum Communication and Quantum Networking, QuantumCom 2009, held in Naples, Italy, in October 2009. The 38 full papers were selected from numerous submissions. This conference has been devoted to the discussion of new challenges in quantum communication and quantum networking that extends from the nanoscale devices to global satellite communication networks. It placed particular emphasis on basic quantum science effects and on emerging technological solutions leading to practical applications in the communication industry, culminating with a special section on Hybrid Information Processing.

Sources of Photonic Entanglement for Applications in Space

Sources of Photonic Entanglement for Applications in Space
Author: Fabian Steinlechner
Publisher:
Total Pages: 171
Release: 2016
Genre:
ISBN:

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The nonlocal correlations of entangled systems are a feature inherent to quantum theory that is fundamentally at odds with our common-sense notions of realism and locality. Additionally, entanglement is an essential resource for numerous quantum communication protocols such as quantum teleportation and quantum dense coding, quantum cryptography, as well as quantum-enhanced metrological schemes and quantum computation. These quantum schemes allow for significant gains in performance over their classical counterparts, and a commercial implementation of protocols utilizing entangled photons thus seems likely in the foreseeable future. A key challenge to be addressed, in order to achieve a global-scale implementation of quantum-enhanced protocols, is the distribution of entanglement over long distances. While photons are in many ways ideal carriers of quantum information, their distribution over long distances is significantly impeded by losses. At present, loss in optical fiber links or atmospheric attenuation and obstructions of the line of sight in terrestrial free-space links limit the distribution of photonic entanglement to several hundred kilometers. Installing sources of photons with quantum correlations on space platforms would allow such distance limitations to be overcome. This would not only lead to the first global-scale implementation of quantum communication protocols, but would also create the opportunity for a completely new class of quantum experiments in a general relativistic framework. State-of-the-art laboratory sources of entangled photons are generally ill-suited for applications in harsh environments such as space, either owing to the use of bulky lasers, the requirement for active interferometric stabilization, or insufficient photon-pair-generation efficiency. Thus, an integral milestone for the experimental implementation of quantum communication protocols over satellite links is the development of robust, space-proof sources of entangled photons with high brightness and entanglement visibility. This thesis is intended to bridge laboratory experiments and real-world applications of quantum entanglement in harsh operational conditions. To this end, the main results of this thesis are: Highly efficient sources of polarization-entangled photons for the distribution of entanglement via long-distance free-space links. The sources are very robust and compact, and incorporate only components which are compliant with the severe requirements of space flight and operation. Optimization of spectral properties and fiber-coupling efficiency of photon pairs generated via spontaneous parametric down-conversion in bulk periodically poled potassium titanyl phosphate. The results of these studies are of great practical relevance for the development of an ultra-stable and efficient entangled photon source. Engineering and characterization of field-deployable polarization-entangled photon sources with high visibility (>99%) and record pair-detection rates (>3 million detected pairs per mW of pump power). As a result of the performance demonstrated, the sources developed have been incorporated into ongoing experiments, for example in quantum nanophotonics and quantum communications, and will provide an enabling tool for future real-world applications.

High-dimensional Entanglement-based Quantum Key Distribution

High-dimensional Entanglement-based Quantum Key Distribution
Author: Tian Zhong (Ph. D.)
Publisher:
Total Pages: 148
Release: 2013
Genre:
ISBN:

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Conventional quantum key distribution (QKD) uses a discrete two-dimensional Hilbert space for key encoding, such as the polarization state of a single photon. In contrast, high-dimensional QKD allows encoding onto a larger state space, such as multiple levels of a continuous variable of a single photon, thus enabling the system to achieve higher photon information efficiency (bits/photon) and potentially higher key rate (bits/second). However, its deployment requires high-performance source, detector, and routing technologies tailored to the specific large-alphabet encoding scheme. One such high-dimensional QKD system of interest is based on time-energy entanglement, in which keys are derived from the arrival times of photon pairs generated from continuous-wave (CW) spontaneous parametric downconversion (SPDC). This thesis focuses on the implementation of a time-energy entanglement-based QKD system, with the development of several enabling technologies including an efficient single-spatial-mode source of time-energy entangled photons based on a periodically-poled KTiOPO4 (PPKTP) waveguide, GHz self-differencing InGaAs singlephoton avalanche diodes (SPADs), and the first demonstration of non-locally dispersion-canceled Franson quantum interferometry achieving 99.6% visibility. We then utilize these technologies to perform two full QKD protocols. The first protocol uses SPDCgenerated entangled photons for both key extraction and Franson interferometry, yielding a secure key rate -90 kbits/s with up to 4 bits/photon after error-correction and privacy amplification. The second protocol deploys two different photon sources: an amplified spontaneous emission (ASE) source is pulse-position modulated to perform random key generation, and a CW-SPDC source is for Franson security check. In this latter case, we have achieved a secure key rate 7.3 Mbits/s with 2.9 bits/photon, which represents the state-of-the-art in today's QKD technology.

Cryptography

Cryptography
Author: Riccardo Bernardini
Publisher: BoD – Books on Demand
Total Pages: 154
Release: 2021-08-18
Genre: Computers
ISBN: 1839625651

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Despite being 2000 years old, cryptography is still a very active field of research. New needs and application fields, like privacy, the Internet of Things (IoT), physically unclonable functions (PUFs), post-quantum cryptography, and quantum key distribution, will keep fueling the work in this field. This book discusses quantum cryptography, lightweight cryptography for IoT, PUFs, cryptanalysis, and more. It provides a snapshot of some recent research results in the field, providing readers with some useful tools and stimulating new ideas and applications for future investigation.

Free Space Quantum Key Distribution to Moving Platforms

Free Space Quantum Key Distribution to Moving Platforms
Author: Christopher J. Pugh
Publisher:
Total Pages: 242
Release: 2017
Genre: Artificial satellites
ISBN:

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The quantum space age has officially begun and many important milestones and achievements have recently been demonstrated, such as the exciting launch and results of the first quantum demonstration satellite, Micius. Previously with terrestrial applications, quantum key distribution was limited in distance to a few hundred kilometers through either free space or optical fiber. This had dampened progress towards a global quantum cryptographic network, but with the recent progress towards space implemented quantum systems, the door has been opened once again. In this thesis, we begin by studying the effect of using an adaptive optics system to improve the efficiency of a free space link to a satellite for quantum key distribution. Adaptive optics has been used extensively in astronomy and has the potential to increase the average optical intensity received by the satellite. We study the effect of the atmosphere on the beam as it propagates from the ground station to the satellite. In the up-link configuration, the atmosphere is of special concern as it affects the beam at the beginning of the propagation, making the end effect worse. One of the important components of a free space quantum key distribution satellite system is a fine pointing unit. We have, along with industry partners, designed and implemented such a unit for free space optical links. The device was designed to have little to no effect on the polarization of the photons used to transmit the key bits. The device was tested, both in the laboratory and outside and quantum key distribution was successfully performed while the fine pointing was active. The main experiment of the thesis demonstrates quantum key distribution to a moving airplane from a ground station. The components of a quantum key distribution receiver prototype were tested locally around the University of Waterloo campus as well as some tests using private airplanes. The collaboration with the National Research Council of Canada really allowed the project to take flight by granting us access to a research aircraft to deploy our receiver prototype. This project spanned over three years and culminated in a two week flight campaign out of Ottawa and Smiths Falls Ontario. Using only five flight hours we were able to successfully transmit finite size quantum secure keys from our optical ground station, located at Smiths Falls--Montague Airport to a Twin Otter Research Aircraft housing our quantum key distribution receiver prototype. Many of the components implemented in the receiver were designed and built with spaceflight in mind and have a clear path to flight for space application. Finally, we study the feasibility of implementing a quantum key distribution receiver onto a nano satellite. In partnership with the University of Toronto Institute for Aerospace Studies Space Flight Laboratory, we studied the various aspects such as optics, detection, cooling, power, mass, etc., to determine if it would be possible to perform quantum key distribution to a nano satellite. The main difference of this project from the previous Quantum Encryption and Science Satellite is the simpler pointing system, which doesn't utilize fine pointing. Through various studies, experiments, and component design, we have shown the feasibility of implementing quantum key distribution to a moving aircraft in an up-link configuration. This work contributes to the long line of achievements leading towards satellite implementations of quantum key distribution for eventual global quantum cryptography.

Single-Photon Generation and Detection

Single-Photon Generation and Detection
Author:
Publisher: Academic Press
Total Pages: 593
Release: 2013-11-29
Genre: Science
ISBN: 0123876966

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Single-photon generation and detection is at the forefront of modern optical physics research. This book is intended to provide a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared. The use of single photons, produced on demand with well-defined quantum properties, offers an unprecedented set of capabilities that are central to the new area of quantum information and are of revolutionary importance in areas that range from the traditional, such as high sensitivity detection for astronomy, remote sensing, and medical diagnostics, to the exotic, such as secretive surveillance and very long communication links for data transmission on interplanetary missions. The goal of this volume is to provide researchers with a comprehensive overview of the technology and techniques that are available to enable them to better design an experimental plan for its intended purpose. The book will be broken into chapters focused specifically on the development and capabilities of the available detectors and sources to allow a comparative understanding to be developed by the reader along with and idea of how the field is progressing and what can be expected in the near future. Along with this technology, we will include chapters devoted to the applications of this technology, which is in fact much of the driver for its development. This is set to become the go-to reference for this field. Covers all the basic aspects needed to perform single-photon experiments and serves as the first reference to any newcomer who would like to produce an experimental design that incorporates the latest techniques Provides a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared, thus giving broad background that should enable newcomers to the field to make rapid progress in gaining proficiency Written by leading experts in the field, among which, the leading Editor is recognized as having laid down the roadmap, thus providing the reader with an authenticated and reliable source

Photon Counting Applications, Quantum Optics, and Quantum Cryptography

Photon Counting Applications, Quantum Optics, and Quantum Cryptography
Author: Ivan Prochazka
Publisher: SPIE-International Society for Optical Engineering
Total Pages: 294
Release: 2007
Genre: Language Arts & Disciplines
ISBN:

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Proceedings of SPIE present the original research papers presented at SPIE conferences and other high-quality conferences in the broad-ranging fields of optics and photonics. These books provide prompt access to the latest innovations in research and technology in their respective fields. Proceedings of SPIE are among the most cited references in patent literature.