Quantum Key Distribution over Probabilistic Quantum Repeaters

A feasible route towards implementing long-distance quantum key distribution (QKD) systems relies on probabilistic schemes for entanglement distribution and swapping as proposed in the work of Duan, Lukin, Cirac, and Zoller (DLCZ) [Nature 414, 413 (2001)]. Here, we calculate the conditional throughput and fidelity of entanglement for DLCZ quantum repeaters, by accounting for the DLCZ self-purification property, in the presence of multiple excitations in the ensemble memories as well as loss and other sources of inefficiency in the channel and measurement modules. We then use our results to find the generation rate of secure key bits for QKD systems that rely on DLCZ quantum repeaters. We compare the key generation rate per logical memory employed in the two cases of with and without a repeater node. We find the cross-over distance beyond which the repeater system outperforms the non-repeater one. That provides us with the optimum inter-node distancing in quantum repeater systems. We also find the optimal excitation probability at which the QKD rate peaks. Such an optimum probability, in most regimes of interest, is insensitive to the total distance.Comment: 12 pages, 6 figures; Fig. 5(a) is replace

Autophagy gene activity may act as a key factor for sensitivity of tumor cells to oncolytic vesicular stomatitis virus

Background: Beclin1 is an important, primary molecule for autophagy. Objectives: It is suggested that the control of the autophagy path increases the sensitivity of tumor cells to VSV. Materials and Methods: In this study, the degree of Beclin1 gene expression in two cell lines, HeLa and A549, has been examined and the percentage of living cells subsequent infection with virus has been evaluated by MTT assay method. Results: The results showed that the degree of Beclin1 gene expression in HeLa cells in comparison with A549 cells has reduced, and the sensitivity of these cells to vesicular stomatits virus (VSV) oncolysis is more than A549. Conclusions: It seems that by using some methods for reducing autophagy, it is possible to make tumor cells more sensitive to virotherapy and even other treatments. © 2016, Iranian Journal of Cancer Prevention

Reactive power control in micro-grid networks using adaptive control

Purpose. Despite their economic and environmental benefits, distributed products in power systems have caused problems in power systems. One of the most important issues in this regard is voltage fluctuations and frequencies in Micro-grids, which depends on several factors, such as variable consumption load and errors in powersystems. One of the main challenges associated with the use of Micro-grids is power management among distributed generation sources. Power management plays a pivotal role in numerous Micro-grids and may ensure the stable and improved performance of Micro-grids in the permanent status of the system. The present study aimed to examine the power control in Micro-grids by proposing an adaptive control method along with the PID controller for power management and coordination in Micro-grids. This coordination system operates between production sources and controlling the voltage and frequency levels against the possible disturbances occurring anywhere in the system loop. The results of the simulation of the proposed algorithm in MATLAB software environment exhibited a high success rate (i.e., proper response to the fluctuations in the Micro-grid) and extremely low error rate (i.e., proper reactive power in the grid).Цель. Несмотря на их экономические и экологические преимущества, распределенные продукты в энергосистемах приводят к возникновению проблем в последних. Одним из наиболее важных вопросов в этой связи являются колебания напряжения и частоты в микросетях, которые зависят от нескольких факторов, таких как переменная нагрузка потребления и ошибки в энергосистемах. Одной из основных проблем, связанных с использованием микросетей, является энерго-менеджмент источников распределенной генерации. Энерго-менеджмент играет ключевую роль во многих микросетях и может обеспечить стабильную и улучшенную работу микросетей при постоянном состоянии системы. Настоящее исследование направлено на исследование энерго-менеджмента в микросетях путем предложения адаптивного метода управления вместе с ПИД-контроллером для энерго-менеджмента и координации в микросетях. Эта система координации функционирует между источниками производимой энергии и контролирует уровни напряжения и частоты в отношении возможных помех, возникающих в любом месте контура системы. Результаты моделирования предложенного алгоритма в программной среде MATLAB показали высокую степень успеха(то есть правильную реакцию на колебания в микросети) и чрезвычайно низкую частоту ошибок(то есть надлежащую реактивную мощность в сети)

REACTIVE POWER CONTROL IN MICRO-GRID NETWORKS USING ADAPTIVE CONTROL

Purpose. Despite their economic and environmental benefits, distributed products in power systems have caused problems in power systems. One of the most important issues in this regard is voltage fluctuations and frequencies in Micro-grids, which depends on several factors, such as variable consumption load and errors in power systems. One of the main challenges associated with the use of Micro-grids is power management among distributed generation sources. Power management plays a pivotal role in numerous Micro-grids and may ensure the stable and improved performance of Micro-grids in the permanent status of the system. The present study aimed to examine the power control in Micro-grids by proposing an adaptive control method along with the PID controller for power management and coordination in Micro-grids. This coordination system operates between production sources and controlling the voltage and frequency levels against the possible disturbances occurring anywhere in the system loop. The results of the simulation of the proposed algorithm in MATLAB software environment exhibited a high success rate (i.e., proper response to the fluctuations in the Micro-grid) and extremely low error rate (i.e., proper reactive power in the grid).Цель. Несмотря на их экономические и экологические преимущества, распределенные продукты в энергосистемах приводят к возникновению проблем в последних. Одним из наиболее важных вопросов в этой связи являются колебания напряжения и частоты в микросетях, которые зависят от нескольких факторов, таких как переменная нагрузка потребления и ошибки в энергосистемах. Одной из основных проблем, связанных с использованием микросетей, является энергоменеджмент источников распределенной генерации. Энергоменеджмент играет ключевую роль во многих микросетях и может обеспечить стабильную и улучшенную работу микросетей при постоянном состоянии системы. Настоящее исследование направлено на исследование энергоменеджмента в микросетях путем предложения адаптивного метода управления вместе с ПИД-контроллером для энергоменеджмента и координации в микросетях. Эта система координации функционирует между источниками производимой  энергии и контролирует уровни напряжения и частоты в отношении возможных помех, возникающих в любом месте контура системы. Результаты моделирования предложенного алгоритма в программной среде MATLAB показали высокую степень успеха (то есть правильную реакцию на колебания в микросети) и чрезвычайно низкую частоту ошибок (то есть надлежащую реактивную мощность в сети)

Confinement interaction in nonlinear generalizations of the Wick-Cutkosky model

We consider nonlinear-mediating-field generalizations of the Wick-Cutkosky model. Using an iterative approach and eliminating the mediating field by means of the covariant Green function we arrive at a Lagrangian density containing many-point time-nonlocal interaction terms. In low-order approximations of $\phi^3{+}\phi^4$ theory we obtain the usual two-current interaction as well as a three-current interaction of a confining type. The same result is obtained without approximation for a version of the dipole model. The transition to the Hamiltonian formalism and subsequent canonical quantization is performed with time non-locality taken into account approximately. A relativistic three-particle wave equation is derived variationally by using a three-particle Fock space trial state. The non-relativistic limit of this equation is obtained and its properties are analyzed and discussed.Comment: 15 pages, 1 figure, LaTe