scholarly journals Optical Quantum Memory and its Applications in Quantum Communication Systems

Author(s):  
Lijun Ma ◽  
Oliver Slattery ◽  
Xiao Tang

Optical quantum memory is a device that can store the quantum state of photons and retrieve it on demand and with high fidelity. It is emerging as an essential device to enhance security, speed, scalability, and performance of many quantum systems used in communications, computing, metrology, and more. In this paper, we will specifically consider the impact of optical quantum memory on quantum communications systems. Following a general overview of the theoretical and experimental research progress in optical quantum memory, we will outline its role in quantum communications, including as a photon source, photon interference, quantum key distribution (QKD), quantum teleportation, quantum repeater, and quantum networks.

Author(s):  
Lijun Ma ◽  
Oliver Slattery ◽  
Xiao Tang

Optical quantum memory is a device that can store the quantum state of photons and retrieve it on demand and with high fidelity. It is emerging as an essential device to enhance security, speed, scalability, and performance of many quantum systems used in communications, computing, metrology, and more. In this paper, we will specifically consider the impact of optical quantum memory on quantum communications systems. Following a general overview of the theoretical and experimental research progress in optical quantum memory, we will outline its role in quantum communications, including as a photon source, photon interference, quantum key distribution (QKD), quantum teleportation, quantum repeater, and quantum networks.


Science ◽  
2017 ◽  
Vol 357 (6358) ◽  
pp. 1392-1395 ◽  
Author(s):  
Tian Zhong ◽  
Jonathan M. Kindem ◽  
John G. Bartholomew ◽  
Jake Rochman ◽  
Ioana Craiciu ◽  
...  

Optical quantum memories are essential elements in quantum networks for long-distance distribution of quantum entanglement. Scalable development of quantum network nodes requires on-chip qubit storage functionality with control of the readout time. We demonstrate a high-fidelity nanophotonic quantum memory based on a mesoscopic neodymium ensemble coupled to a photonic crystal cavity. The nanocavity enables >95% spin polarization for efficient initialization of the atomic frequency comb memory and time bin–selective readout through an enhanced optical Stark shift of the comb frequencies. Our solid-state memory is integrable with other chip-scale photon source and detector devices for multiplexed quantum and classical information processing at the network nodes.


2005 ◽  
pp. 53-68 ◽  
Author(s):  
R. Kapeliushnikov ◽  
N. Demina

The paper provides new survey evidence on effects of concentrated ownership upon investment and performance in Russian industrial enterprises. Authors trace major changes in their ownership profile, assess pace of post-privatization redistribution of shareholdings and provide evidence on ownership concentration in the Russian industry. The major econometric findings are that the first largest shareholding is negatively associated with the firm’s investment and performance but surprisingly the second largest shareholding is positively associated with them. Moreover, these relationships do not depend on identity of majority shareholders. These results are consistent with the assumption that the entrenched controlling owners are engaged in extracting "control premium" but sizable shareholdings accumulated by other blockholders may put brakes on their expropriating behavior and thus be conductive for efficiency enhancing. The most interesting topic for further more detailed analysis is formation, stability and roles of coalitions of large blockholders in the corporate sector of post-socialist countries.


2019 ◽  
Vol 10 (2) ◽  
pp. 144-151
Author(s):  
Noora Ahmed Lari ◽  

The State of Qatar has implemented several family policies in order to improve the wellbeing of Qatari families and ensure fair distribution of development benefits for both men and women. However, there is a linkage between female employment outside the home and instability in the marriages of Qatari families. This paper investigates the impact of female employment on marital stability, based on the results of primary data collected in Qatar, a questionnaire that consisted of several sections such as challenges in the workplace, supervisor, family and spouse relations, work motivation and performance. Of the 824 questionnaires that were returned, 807 were completed and valid for analysis. Regression analysis and an ANOVA test have been used to test the relationship between the variables. The results of the research have produced mixed findings about how wives’ employment increases marital instability and have yielded few significant differences on mean scores of discuss on work demands, insufficient time together, housework, financial matters, communication, relatives and rearing children. The results indicates that in general Qatar working women face several challenges in relation to their marital life as part of cultural and social constraints.


2018 ◽  
Vol 12 (2) ◽  
pp. 60-63
Author(s):  
Mariana Sandu ◽  
Stefan Mantea

Abstract Agri-food systems include branching ramifications, which connect in the upstream the input suppliers with farmers, and downstream farmers, processors, retailers and consumers. In the last decades, at the level of the regions, food systems have undergone rapid transformation as a result of technological progress. The paper analyzes the changes made to the structure, behavior and performance of the agri-food system and the impact on farmers and consumers. Also, the role of agricultural research as a determinant factor of transformation of agri-food system is analyzed. The research objective is to develop technologies that cover the entire food chain (from farm to fork) and meet the specific requirements of consumers (from fork to farm) through scientific solutions in line with the principles of sustainable agriculture and ensuring the safety and food safety of the population.


2020 ◽  
Vol 26 (2) ◽  
pp. 299-315
Author(s):  
V.V. Smirnov

Subject. The article discusses the momentum in finance. Objectives. The study reveals the impact of financial momentum as the unity of antipodes in the development of the national economy. Methods. The study is based on a systems approach and methods of descriptive statistics. Results. I discover the ultimate goal of globalization, i.e. the substantive simplification of national economies and strengthening of global economic ties. The goals determine the logic tendency of national economies for reducing the interest rate so as to gain the financial momentum and, consequently, fanning the crisis risk in the global financial system. The global financial system became the substance of global economic processes, which determined development opportunities of national economies. I reveal what countries have the high and low financial momentum. Conclusions and Relevance. Being the unity of antipodes in the modern economic development, financial momentum causes countries to lose their economic identity, making them just functions of the global financial system. The cyclical development model of national economies is replaced with the metron model that rests on fluctuating advanced economies with the low financial momentum at its bottom and emerging economies at its top. The findings crystallize the concept and new competencies for a person who decide on the determination and performance of financial regulation activities.


Author(s):  
Ana Rita Damas Oliveira ◽  
Paulo Alexandre Guedes Lopes Henriques ◽  
Teresa Cristina Clímaco Monteiro de Oliveira

Much has been written about the link between HR and performance, however consensus has yet not been found concerning the understanding on how that relationship comes together. Empirically, no direct impact has been found and research has only suggested an indirect impact. Consequently, the Strategic HRM field is particularly interested on the understanding of the mediating variables that impact the organization performance. Besides the integrated and business strategy alignment of the HR function, it should be considered that it is the people (HR) of the organization and not their practices that determine the company´s competitive advantage. (Messersmith & Guthrie, 2010) argue that it is the impact of those practices that represent “the true resource and enable a sustainable advantage over industry rivals”. The objetive of this research proposal is to study the impact of strategic human resources practices on the organization performance through a case study methodology, supported by longitudinal data. Namely, the project aims to achieve a deeper understanding of the variables that affect the process stream during strategy implementation. How the HR practices impact on people? And why human resources are the most valuable asset? These core premises are in line with the most recent economic concerns about people productivity, employment policies and labor flexibility.


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