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

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

Why didn’t Russia become a constitutional monarchy in the XIX century?

The article deals with the main problems associated with the possibility of implementing a constitutional alternative in Russia in the XIX century. The authors consider the prerequisites for the development of constitutional projects during this period, including their regularity or randomness, and relationship with previous stages of development of the Russian statehood. They pay particular attention to the subjective factor, i.e. personal views and worldview of the Russian emperors as the main condition for the implementation of the constitutional alternative to the development of the country. The reigns of Alexander I and Alexander II, who were either the initiators of the development of constitutional projects (Alexander I) or did not prevent it (Alexander II), are the focus of attention. The comparative analysis of the main constitutional projects of the XIX century is carried out in this article: of the Letter of Commendation to the Russian people in 1801, the project of M.M. Speransky in 1809, the Charter Diploma of the Russian Empire in 1818-1820, the project of P.A. Valuev in 1863, the grand prince Konstantin Nikolaevich in 1866 and 1880, the P.A. Shuvalov in 1874 and of the M.T. Loris-Melikov in 1880-1881.The projects of the time period of Alexander II are much more moderate than of the epoch of Alexander I and they can be recognized as constitutional ones with a great stretch. It was a step backwards in the development of Russian constitutionalism. This is explained by a subjective factor: much more moderate political views of Alexander II and his greater commitment to the autocratic tradition inherited from his father. In conclusion, there are the reasons for the lack of implementation of the constitutional alternative in Russia in the XIX century in this article, they are the following: peculiarities of the social structure of the Russian society, narrowness of the social base of the constitutional reforms, lack of understanding and disinterestedness of the majority of the population in their implementation and necessity, indecision of the emperors

The Coronavirus against Decentralization: Risks of and Challenges for the Development of United Territorial Communities in the context of the Pandemic

The article highlights the current problems of and challenges for the development of united territorial communities in the context of decentralization and the pandemic. The spatial development of territorial communities is the main goal in the framework of implementing the decentralization reform, which is aimed at ensuring a high quality of life of the population and competitiveness of the national economy under conditions ofthe crisis and pandemic. The economic and social consequences of the coronavirus outbreak,which has captured the whole world, did not bypass Ukraine and its territorial units.The aim of the article is to identify the problems of the development of united territorial communities in the context of decentralization and the pandemic and to develop areas of anti-crisis measures for overcoming the problems andcreatingcompetitive advantages of united territorial communities.The low pace of development of united territorial communities reveals the presence of problems associated with their sufficient resource provision; efficient distribution of powers and responsibilities among the levels of government; validity of the criteria for uniting territorial communities; lack of sufficient management qualifications to elaborate effective strategies, programs, and projects for the development of united territorial communities. Moreover, it indicates their significant financial dependence on government support.The main problems of budget losses of united territorial communities due to the coronavirus pandemic and anti-crisis measures to support the population and entrepreneurship are identified. A roadmap of state support for the development of UTCs, defining the measures, timing of their implementation, and the responsible authorities is created

Cavityless self-organization of ultracold atoms due to the feedback-induced phase transition

Feedback is a general idea of modifying system behaviour depending on the measurement outcomes. It spreads from natural sciences, engineering, and artificial intelligence to contemporary classical and rock music. Recently, feedback has been suggested as a tool to induce phase transitions beyond the dissipative ones and tune their universality class. Here, we propose and theoretically investigate a system possessing such a feedback-induced phase transition. The system contains a Bose-Einstein condensate placed in an optical potential with the depth that is feedback-controlled according to the intensity of the Bragg-reflected probe light. We show that there is a critical value of the feedback gain where the uniform gas distribution loses its stability and the ordered periodic density distribution emerges. Due to the external feedback, the presence of a cavity is not necessary for this type of atomic self-organization. We analyze the dynamics after a sudden change of the feedback control parameter. The feedback time constant is shown to determine the relaxation above the critical point. We show as well that the control algorithm with the derivative of the measured signal dramatically decreases the transient time

Innovation activity of Russian business entities and its determinants

Market growth prospects of the entities during the innovation activity could not be sized up due to lack of systematized and shared view at factors defining the innovation activity of business entities. The paper presents key factors of innovation activity along with its classification by levels (macro, meso, and micro). Authors suggested a specific innovation activity evaluation framework as well as multivariate regression model of assessing the structure and key-factors’ effect on business activity is developed.peer-reviewe

The optimality of the option of abolishing serfdom in Russia, implemented in 1861

The article discusses the controversial issues related to the abolition of serfdom in Russia in 1861: its causes, features of preparation and implementation. The authors focus on the question of whether the implemented version of the abolition of serfdom in Russia was optimal. For this purpose, a comparative analysis of the abolition of serfdom in Russia is carried out with similar reforms in European countries, which could serve as a reference point, primarily in Austria and Prussia. It is concluded that the peasant reform in Russia in 1861 (in the final version) was carried out primarily in the interests of the state and not of individual social groups (landowners and peasants). It is the state that has benefited most from the implementation of this particular version of the reform, both financially and politically. Among the losers there were both peasants (to a greater extent) and landowners (to a lesser extent). The main thing was that the reform provoked the problem of the lack of land of the majority of peasants, which in the future became one of the main reasons for the social explosion and revolutions at the beginning of the XX century

Methodical Approach to Identifying Problems in the Functioning of Territorial Communities Caused by Unstable Environments

The article deals with the topical problem of spatial development of territorial communities. The study aims at creating a methodical approach to identifying the problems in the functioning of territorial communities, the former being caused by unstable conditions, and the areas of spatial development of territories using a problem-oriented approach. The application of a problem-oriented approach to the spatial development of territorial communities is substantiated. The approach provides a set of actions in public administration and influences aimed at solving theoretical or practical problems of efficiently using local community resources by gaining new competitive advantages, creating favorable living conditions, ensuring population loyalty through actively solving the already existing and possible problems in community functioning. Within the problem-oriented framework, the spatial development of united territorial communities involves an approach based on the hypothesis that using the strategic capacity of a territorial community is not a problem-free process, and the arising problems require analysis and sound management decisions at the community level and within the powers of local authorities. A methodical approach to identifying problems with the functioning of territorial communities in an unstable environment is suggested. Namely, it involves analyzing the following issues: a) development level of united territorial communities through evaluating their resource provision and self-assessment of their development level, which helps to draw conclusions as for the effectiveness of using the community resources; b) legislative support for the spatial development of territorial communities; and c) the existing mechanisms, methods, and instruments of the state policy on the spatial development of Ukrainian territories. A cognitive map of interrelations between the existing problems of the spatial development of territorial communities has been drafted, in which four groups of problems are identified, in particular: 1) problems within the spatial development of territorial communities, and those connected with Ukraine’s territorial system; 2) problems of socio-economic development based on self-sufficiency; 3) problems in the local self-government system; 4) problems of rural development