Dislocation-induced superfluidity in a model supersolid

Motivated by recent experiments on the supersolid behavior of $^4$He, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. Using Landau theory, we couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.Comment: 10 pages, 6 figure

Reading-out the state of a flux qubit by Josephson transmission line solitons

We describe the read-out process of the state of a Josephson flux qubit via solitons in Josephson transmission lines (JTL) as they are in use in the standard rapid single flux quantum (RSFQ) technology. We consider the situation where the information about the state of the qubit is stored in the time delay of the soliton. We analyze dissipative underdamped JTLs, take into account their jitter, and provide estimates of the measuring time and efficiency of the measurement for relevant experimental parameters.Comment: 13 pages, 12 figure

Distinguishing quantum from classical oscillations in a driven phase qubit

Rabi oscillations are coherent transitions in a quantum two-level system under the influence of a resonant perturbation, with a much lower frequency dependent on the perturbation amplitude. These serve as one of the signatures of quantum coherent evolution in mesoscopic systems. It was shown recently [N. Gronbech-Jensen and M. Cirillo, Phys. Rev. Lett. 95, 067001 (2005)] that in phase qubits (current-biased Josephson junctions) this effect can be mimicked by classical oscillations arising due to the anharmonicity of the effective potential. Nevertheless, we find qualitative differences between the classical and quantum effect. First, while the quantum Rabi oscillations can be produced by the subharmonics of the resonant frequency (multiphoton processes), the classical effect also exists when the system is excited at the overtones. Second, the shape of the resonance is, in the classical case, characteristically asymmetric; while quantum resonances are described by symmetric Lorentzians. Third, the anharmonicity of the potential results in the negative shift of the resonant frequency in the classical case, in contrast to the positive Bloch-Siegert shift in the quantum case. We show that in the relevant range of parameters these features allow to confidently distinguish the bona fide Rabi oscillations from their classical Doppelganger.Comment: 8 pages, 4 figures; v2: minor corrections, Fig.1 added, introduction expande

Competing ideologies of Russia's civil society

Many analysts and public opinion makers in the West conflate the notions of Russia’s non-systemic liberal opposition and the country’s civil society. Indeed, despite garnering the support of a minority of Russia’s population, non-systemic liberal opposition represents a well-organized civic group with a clearly articulated agenda and the ability to take action. Yet, does Russia’s civil society end there? A closer look at the country’s politics shows that Russia has a substantial conservative-traditionalist faction that has also developed agenda for action and formulated opinions. This group is anti-liberal rather than illiberal ideologically and pro-strong state/pro a geopolitically independent Russia rather than pro-Kremlin politically. The interaction between liberal and conservative civic groups represents the battle of meanings, ideas, and ethics, and ultimately determines the future trajectory of Russia’s evolution. Thus, the analysis of Russia’s civil society must represent a rather more nuanced picture than a mere study of the liberal non-systemic opposition. This article will examine the complexity of Russia’s civil society scene with reference to the interplay between the liberal opposition and conservative majority factions. The paper will argue that such complexity stems from ideological value pluralism that falls far beyond the boundaries of the liberal consensus, often skewing our understanding of political practice in Russia

Metastable bound state of a pair of two-dimensional spatially separated electrons in anti-parallel magnetic fields

We propose a new mechanism for binding of two equally charged carriers in a double-layer system subjected by a magnetic field of a special form. A field configuration for which the magnetic fields in adjacent layers are equal in magnitude and opposite in direction is considered. In such a field an additional integral of motion - the momentum of the pair P arises. For the case when in one layer the carrier is in the zero (n=0) Landau level while in the other layer - in the first (n=1) Landau level the dependence of the energy of the pair on its momentum E(P} is found. This dependence turns out to be nonmonotonic one : a local maximum and a local minimum appears, indicating the emergence of a metastable bound state of two carrier with the same sign of electrical charge.Comment: 7 page

Critical success factors during the implementation of ISO 22000:2018

Purpose: The purpose of the paper is to evaluate why companies still struggle with ISO 22000 implementation and maintenance, identifying which aspects are key for its success. Design/methodology/approach - A literature review was carried out based on Scientific articles and implementation guides collected from Google Scholar, ScienceDirect and ResearchGate. Findings - Nine aspects seem to have a broader impact on organizations maintenance of ISO 22000 and other FSMS. Furthermore, the empirical research reveals that having an efficient food safety management system is a prerequisite for companys competitiveness. Practical implications - The findings show that many of the critical success factors for a FSMS implementation are based on regular and adequate management of people inside the company. Originality/value - A novel model of segmenting critical success factors is presented, which has practical implications for ISO 22000 achievement.(undefined)info:eu-repo/semantics/publishedVersio

CITIZENSHIP IN THE STRUCTURE OF SOCIO-POLITICAL ORIENTATIONS OF RUSSIAN YOUTH: PLACE AND ROLE IN STATEHOOD STRENGTHENING

Purpose of the study: In this study, we analyze citizenship in the structure of socio-political orientations of Russian youth and explore the youth role in strengthening statehood and formation of civil society institutions. The development of active citizenship values in sociopolitical orientations of Russian youth is determined by the need to change relations between the state and society. The citizens shall develop civic responsibility and civil initiatives and control the institutions of power. Methodology: The theory of social anomie and the concept of socio-cultural crisis serve the methodological basis for this study. This theory explores the eclectic nature of citizenship ideas in the youth environment. The civilizational approach makes it possible to investigate features of citizenship idea and practice information of Western European and Russian cultural traditions. All that is methodologically significant in tracking citizenship specificity of the Russian youth. The integrated approach becomes a conceptual one in this study as it treats the citizenship of Russian youth as a complex multi-component phenomenon. This phenomenon includes moral, legal and socio-political attitudes reflecting the various aspects of relations in the "man-society-state" system. Results: We conclude that in the citizenship of Russian youth there dominate two main attitudes: liberal and paternalistic. In the liberal aspect, the young people consider citizenship to be awareness of their civil rights and responsibilities, a kind of rational and active behavior corresponding to democratic political system. Paternalistic attitudes are manifested in loyalty to the state. Paternalists consider the state to be the political institution that is solely responsible for the present and future of the young people. Applications of this study: The results allow us to understand the significance of citizenship as an ethic-legal quality of personality that strengthens Russian statehood and the importance of agreement (contract) between government and society. The results discovered the need for the citizens to be engaged in solving the state's socially significant problems. The state shall also develop a favorable institutional environment for civil socialization and self-realization of the young people. Novelty/Originality of this study: The eclectic nature of Russian youth citizenship points at hindering factors in the development of active and responsible citizenship as the youth ability to self-organize and solve socially significant problems. The main factors hindering the process of civil activity formation among the young people are the stable etatist-paternalistic traditions of political culture and institutions of Russian civil society. Although, development of youth citizenship is a well-managed process. It requires the youth policy to be the stimulating and guiding force. This force is necessary to solve the problems of legal personality type formation. Such a personality is characterized by politically and socially active civic-mindedness