Incoherent quantum feedback control of collective light scattering by Bose-Einstein condensates

It is well known that in the presence of a ring cavity the light scattering from a uniform atomic ensemble can become unstable resulting in the collective atomic recoil lasing. This is the result of a positive feedback due to the cavity. We propose to add an additional electronic feedback loop based on the photodetection of the scattered light. The advantage is a great flexibility in choosing the feedback algorithm, since manipulations with electric signals are very well developed. In this paper we address the application of such a feedback to atoms in the Bose-Einstein condensed state and explore the quantum noise due to the incoherent feedback action. We show that although the feedback based on the photodetection does not change the local stability of the initial uniform distribution with respect to small disturbances, it reduces the region of attraction of the uniform equilibrium. The feedback-induced nonlinearity enables quantum fluctuations to bring the system out of the stability region and cause an exponential growth even if the uniform state is globally stable without the feedback. Using numerical solution of the feedback master equation we show that there is no feedback-induced noise in the quadratures of the excited atomic and light modes. The feedback loop, however, introduces additional noise into the number of quanta of these modes. Importantly, the feedback opens an opportunity to position the modulated BEC inside a cavity as well as tune the phase of scattered light. This can find applications in precision measurements and quantum simulations.Comment: 7 pages, 7 figure

Join Execution Using Fragmented Columnar Indices on GPU and MIC

The paper describes an approach to the parallel natural join execution on computing clusters with GPU and MIC Coprocessors. This approach is based on a decomposition of natural join relational operator using the column indices and domain-interval fragmentation. This decomposition admits parallel executing the resource-intensive relational operators without data transfers. All column index fragments are stored in main memory. To process the join of two relations, each pair of index fragments corresponding to particular domain interval is joined on a separate processor core. Described approach allows efficient parallel query processing for very large databases on modern computing cluster systems with many-core accelerators. A prototype of the DBMS coprocessor system was implemented using this technique. The results of computational experiments for GPU and Xeon Phi are presented. These results confirm the efficiency of proposed approach

The Strategy of Enterprise’s Competitive Advantages Formation Under Condition of Intensive Competitive Struggle Стратегия формирования конкурентных преимуществ предприятия в условиях интенсивной конкурентной борьбы

In the article the sequence of development stages of strategy of the enterprise’s competitive advantages formation in the conditions of high intensity of competitive struggle is considered. The system of information streams, and also requirements to competitive advantages depending on type of competitive strategy is offered.В статье рассмотрена последовательность этапов разработки стратегии формирования конкурентных преимуществ предприятия в условиях высокой интенсивности конкурентной борьбы. Предложена система информационных потоков, а также требования к конкурентным преимуществам в зависимости от типа конкурентной стратегии

COMPARATIVE STUDY OF PATIENTS AND HEALTHY CARRIERS OF ANTIBODIES AGAINST VARICELLAZOSTER VIRUS

The degree of seropositiveness against Varicella-zoster virus (VZV) were established by examination of 737 single serum samples from clinically healthy donors aged 1-60 years by using CF-test. Comparatively, 91 of them were studied by ELISA (Behring-Germany, Ensygnost-Varicella-Zoster). Additionally, 37 single serum samples of patients with clinical symptoms of herpes zoster were examined by CF-test. The results of the healthy population showed a mean seroprevalence of 48,98 % by CF-test and of 60,44 % by ELISA. The difference of seroprevalence of healthy and ill individuals (with typical clinical signs) in matched age intervals was considerable only with patients suffering from herpes zoster

Understanding How Components of Organisations Contribute to Attacks

Attacks on organisations today explore many different layers, including buildings infrastructure, IT infrastructure, and human factor – the physical, virtual, and social layer. Identifying possible attacks, understanding their impact, and attributing their origin and contributing factors is difficult. Recently, system models have been used for automatically identifying possible attacks on the modelled organisation. The generated attacks consider all three layers, making the contribution of building infrastructure, computer infrastructure, and humans (insiders and outsiders) explicit. However, this contribution is only visible in the attack trees as part of the performed steps; it cannot be mapped back to the model directly since the actions usually involve several elements (attacker and targeted actor or asset). Especially for large attack trees, understanding the relations between several model components quickly results in a large quantity of interrelations, which are hard to grasp. In this work we present several approaches for visualising attributes of attacks such as likelihood of success, impact, and required time or skill level. The resulting visualisations provide a link between attacks on an organisations and the contribution of parts of an organisation to the attack and its impact