Chemical potential of quasi-equilibrium magnon gas driven by pure spin current

We show experimentally that the spin current generated by the spin Hall effect drives the magnon gas in a ferromagnet into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of spin current-driven Bose-Einstein condensation

Differential Calculus on qq-Deformed Light-Cone

We propose the ``short'' version of q-deformed differential calculus on the light-cone using twistor representation. The commutation relations between coordinates and momenta are obtained. The quasi-classical limit introduced gives an exact shape of the off-shell shifting.Comment: 11 pages, Standard LaTeX 2.0

The Ginzburg-Landau model of Bose-Einstein condensation of magnons

We introduce a system of phenomenological equations for Bose-Einstein condensates of magnons in the one-dimensional setting. The nonlinearly coupled equations, written for amplitudes of the right-and left-traveling waves, combine basic features of the Gross-Pitaevskii and complex Ginzburg-Landau models. They include localized source terms, to represent the microwave magnon-pumping field. With the source represented by the $\delta$-functions, we find analytical solutions for symmetric localized states of the magnon condensates. We also predict the existence of asymmetric states with unequal amplitudes of the two components. Numerical simulations demonstrate that all analytically found solutions are stable. With the $\delta$-function terms replaced by broader sources, the simulations reveal a transition from the single-peak stationary symmetric states to multi-peak ones, generated by the modulational instability of extended nonlinear-wave patterns. In the simulations, symmetric initial conditions always converge to symmetric stationary patterns. On the other hand, asymmetric inputs may generate nonstationary asymmetric localized solutions, in the form of traveling or standing waves. Comparison with experimental results demonstrates that the phenomenological equations provide for a reasonably good model for the description of the spatiotemporal dynamics of magnon condensates.Comment: Physical Review B, in pres

h-deformation of Gr(2)

The $h$-deformation of functions on the Grassmann matrix group $Gr(2)$ is presented via a contraction of $Gr_q(2)$. As an interesting point, we have seen that, in the case of the $h$-deformation, both R-matrices of $GL_h(2)$ and $Gr_h(2)$ are the same

Non-standard quantum so(3,2) and its contractions

A full (triangular) quantum deformation of so(3,2) is presented by considering this algebra as the conformal algebra of the 2+1 dimensional Minkowskian spacetime. Non-relativistic contractions are analysed and used to obtain quantum Hopf structures for the conformal algebras of the 2+1 Galilean and Carroll spacetimes. Relations between the latter and the null-plane quantum Poincar\'e algebra are studied.Comment: 9 pages, LaTe

Fact-checking Technology in the Fight Against "Information Debris": Problems and Prospects

This article raises the question of the existence in conditions of post-truth reality, actualises the problem of blurring the distinctions between reliability and unreliability, truth and falsehood, facts and fakes, and states the imperative of the need to confront this. The aim of the work is to analyze methods / rules of fact-checking, which is a technology for determining the reliability of incoming and broadcast information. Nowadays, many disciplines,  especially the sociology of mass communications, are focused on the theoretical content of fact-checking and its set of techniques / practices. Approaches and development results of domestic and foreign researchers of mass media form the methodological basis of this article. As a result, the statement is that knowing rules of fact-checking is not only a professional competence, but an ideological setting for preferring the fact to fake, focused on consolidating the primacy of the value of truth and rejection of lies. The main conclusion is recognition of the need to supplement and consolidate professional information and communication competencies with general cultural ones

Memes, Meme Viruses: Their Essence and Distribution in the Infosphere and Media Space

The article is dedicated to memes, their genesis, essence and typology. The purpose of the research was to analyze the current state of infosphere from memetics perspective. The meth­odology is based on the extrapolation principle of conceptual construct of evolutionary biol­ogy to understanding of the essence of culture and its development. The final conclusion of this research was an assumption that biological evolution continues in cultural. Cultures, which are evaluated as highly developed, spread their values in form of memes: any culture carries out semantic expansion and is aimed at their “advance”. Memes of life-affirming or rational values contribute to preservation and development of culture, and memes of life-rejecting or irrational values lead culture to the dead-end by causing intellectual stagnation in society. The latter could be interpreted as viruses. The environment for appearance and replication of meme-viruses is mass media and mediasphere in general. Based on the findings there are two main theses: there is a need to deal with meme-viruses, which requires improving skills/tech- niques of effective confrontation; it is necessary to develop intellectual immunity, providing a professional handicap to its carrier