5,047 research outputs found
Theory of high-T_c superconductivity based on the fermion-condensation quantum phase transition
A theory of high temperature superconductivity based on the combination of
the fermion-condensation quantum phase transition and the conventional theory
of superconductivity is presented. This theory describes maximum values of the
superconducting gap which can be as big as , with
being the Fermi level. We show that the critical temperature
. If there exists the pseudogap above then
, and is the temperature at which the pseudogap
vanishes. A discontinuity in the specific heat at is calculated. The
transition from conventional superconductors to high- ones as a function
of the doping level is investigated. The single-particle excitations and their
lineshape are also considered.Comment: 6 pages, Revte
“Merciless Merciful Summer” by B. Melkevik: Collective Responsibility and Cancel Culture in Memorial Wars
This article describes the B. Melkevik’s philosophical and legal views on issues related to the legal understanding of collective memory, historical responsibility and collective guilt. The authors fit the researcher’s reasoning into the broad context of the development of ideas about collective responsibility and link the “ethical memory” criticized by B. Melkevik with the “cancel culture” and the spread of “new ethics”, suggesting the possibility of placing blame for the actions of one person on the group with which he identifies. The authors consider the limits of applicability of the concept of “Leta” B. Melkevik, believing that the conventional establishment of a regime of oblivion for historical memory through democratic procedures undermines the expertise of professional historical knowledge that provides a reliable Past. They come to the conclusion that the “cancel culture” characteristic of the digital media environment blocks the Habermas model of communicative rationality used by Melkevik
Media Memory in the Fanfiction Culture: the Image of Peter the Great in Online Literature
Поступила в редакцию: 15.03.2021. Принята к печати: 30.03.2021.Submitted: 15.03.2021. Accepted: 30.03.2021.Статья посвящается рассмотрению образа Петра I в сетевой литературе. Автор использует понятие «медиапамять» для описания феномена существования коллективных представлений о прошлом в медиа-среде. Культура фанфикшн рассматривается как одна из практик конструирования медиапамяти. Анализ художественных любительских текстов на краудсорсинговой платформе «Книга фанфиков» (ficbook.net) выявил способы выстраивания интернет-пользователями своего отношения к истории. Рассмотрение исторических текстов о Петровской эпохе показало, что пользовательские представления о Петре I крайне мифологизированы, основаны на стереотипах, которые преодолеваются свободной интерпретацией и актуализацией фактов прошлого при помощи образов современной массовой культуры.The article is devoted to the consideration of the image of Peter I in the online literature. The author uses the concept of media memory to describe the phenomenon of the existence of collective ideas about the past in the media environment. He considers the culture of fanfiction as one of the practices of constructing media memory. Analysis of amateur art texts on the crowdsourcing platform “Book of Fan Fiction” (ficbook.net) revealed the ways in which Internet users build their attitude to history. The review of historical texts about the Peter the Great era showed that the user’s ideas about Peter the Great are extremely mythologized, based on stereotypes that are overcome by the free interpretation and actualization of the facts of the past, with the help of images of modern mass culture.Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 20-09-42063 «Петр I в исторической памяти современной России: репрезентация образа в медиасреде»
Magnetoresistance of Highly Correlated Electron Liquid
The behavior in magnetic fields of a highly correlated electron liquid
approaching the fermion condensation quantum phase transition from the
disordered phase is considered. We show that at sufficiently high temperatures
the effective mass starts to depend on , . This dependence of the effective mass at elevated
temperatures leads to the non-Fermi liquid behavior of the resistivity,
and at higher temperatures . The
application of a magnetic field restores the common behavior of the
resistivity. The effective mass depends on the magnetic field, , being approximately independent of the temperature at . At , the dependence of the
effective mass is re-established. We demonstrate that this phase diagram
has a strong impact on the magnetoresistance (MR) of the highly correlated
electron liquid. The MR as a function of the temperature exhibits a transition
from the negative values of MR at to the positive values at . Thus, at , MR as a function of the temperature
possesses a node at .Comment: 7 pages, revtex, no figure
Soviet Leaders in Western Media Space
The results of the analysis of the USSR image in Western social media are presented. The novelty of the study lies in the use of the Global Database of Events, Language, and Tone in the analysis of the image of Soviet leaders in the Euro-Atlantic press. A review of messages that mention the names of the leaders of the USSR from January 1, 2017 to the present in the Western press has been completed. It is proved that the overall emotional tone of the narrative about the Soviet leaders in Western media is extremely negative. It is noted that French and German journalists, in comparison with Anglo-Saxon ones, more often write about Soviet history in a positive context. It is emphasized that the differences correlate with the quality of relations between Western countries and Russia, as well as the prospects for their improvement. It is shown that journalists, discussing the Soviet leaders, raise existential questions that are important for the Euro-Atlantic mass consciousness. The relevance of the study is due to the fact that the growth of media interest in the stories of rapprochement between the USSR and the West, as well as the emotionally positive transformation of the images of Soviet leaders in the media is considered as a condition and indicator of improving relations between Russia and the West
Ground state instability in systems of strongly interacting fermions
We analyze stability of a fermion system with model repulsive pair
interaction potential. The possibility for different types of restructuring of
the Fermi ground state (at sufficiently great coupling constant) is related to
the analytic properties of such potential. In particular, for the screened
Coulomb law it is shown that the restructuring cannot be of the Fermi
condensation type, known earlier for some exactly solvable models, and instead
it belongs to the class of topological transitions (TT). For this model, a
phase diagram has been built in the variables "screening parameter - coupling
constant" which displays two kinds of TT: a 5/2-kind similar to the known
Lifshitz transitions in metals, and a 2-kind characteristic for a uniform
strongly interacting system.Comment: The article has 11 pages, in Latex 2e (from Lyx), 3 eps figures or a
ps fil
Flattening of Single-Particle Spectra in Strongly Correlated Electron Systems and the Violation of the Wiedemann-Franz Law
The renormalization of the Wiedemann-Franz (WF) ratio in strongly correlated
electron systems is analyzed within the Landau quasiparticle picture. We
demonstrate that the WF law is violated: (i) at the quantum critical point,
where the effective mass diverges, and (ii) beyond a point of fermion
condensation, where the single-particle spectrum becomes flat.
Results of the analysis are compared with available experimental data.Comment: 6 pages, 5 figures, added reference
Formation of conductive oxide scale on 33NK and 47Nd interconnector alloys for solid oxide fuel cells
Two grades of chromium-free alloys were studied in order to apply them as interconnectors for solid oxide fuel cells. The surface modification methods were proposed for each alloy with the purpose of forming of oxide scales considering the required physicochemical properties. Investigations of the structure and properties of the obtained oxide scales were performed and the efficiency of the chosen surface modification methods was approved. The samples with the surface modification exhibited higher conductivity values in comparison with the nonmodified samples. A compatibility study of samples with surface modification and glass sealant of chosen composition was accomplished. The modified samples demonstrated good adhesion during testing and electrical resistance less than 40 mOhm/cm2 at 850 ◦C in air, which allowed us to recommend these alloys with respective modified oxide scales as interconnectors for SOFC. © 2019 by the authors.Russian Foundation for Basic Research, RFBR: 17-58-10006This research was funded by the Russian Foundation of Basic Research grant number 17-58-10006. The facilities of the shared access center "Composition of Compounds" of IHTE UB RAS were used in this work
Spontaneous breaking of four-fold rotational symmetry in two-dimensional electronic systems explained as a continuous topological transition
The Fermi liquid approach is applied to the problem of spontaneous violation
of the four-fold rotational point-group symmetry () in strongly correlated
two-dimensional electronic systems on a square lattice. The symmetry breaking
is traced to the existence of a topological phase transition. This continuous
transition is triggered when the Fermi line, driven by the quasiparticle
interactions, reaches the van Hove saddle points, where the group velocity
vanishes and the density of states becomes singular. An unconventional Fermi
liquid emerges beyond the implicated quantum critical point.Comment: 6 pages, 4 figure
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