Fermi-liquid theory of the surface impedance of a metal in a normal magnetic field

In this paper we present detailed theoretical analysis of the frequency and/or magnetic field dependence of the surface impedance of a metal at the anomalous skin effect. We calculate the surface impedance in the presence of a magnetic field directed along the normal to the metal surface. The effects of the Fermi-liquid interactions on the surface impedance are studied. It is shown that the cyclotron resonance in a normal magnetic field may be revealed {\it only and exclusively} in such metals whose Fermi surfaces include segments where its Gaussian curvature turns zero. The results could be applied to extract extra informations concerning local anomalies in the Fermi surface curvature in conventional and quasi-two-dimensional metals.Comment: 10 pages, 1 figure, text added and rearranged, computational details are moved into Appendice

Jihad as Passionarity: Said Buriatskii and Lev Gumilev

This article analyses Russian elements in the texts of Said Buriatskii (1982–2010), who in the late 2000s was one of the main ideologists and symbols of the internationalist Islamist resistance in the North Caucasus. Trying to explain the importance and validity of jihad, Buriatskii referred to the concepts of the famous Soviet historian and anthropologist Lev Gumilev and brought Islamic radicalism closer to a Russian-speaking audience by using Gumilev’s terminology. Indeed, he found some appreciation among Russian radical journalists, and even among oppositionists from a background close to the Russian Orthodox Church. This article therefore argues that, in spite of his Islamic rhetoric, Buriatskii can also be understood as aspiring to achieve the status of a Russian public intellectual, particularly as a representative of a broader movement that emphasizes values such as sincerity and passion