3,832 research outputs found
Algebraic Geometry over Free Metabelian Lie Algebra I: U-Algebras and Universal Classes
This paper is the first in a series of three, the aim of which is to lay the
foundations of algebraic geometry over the free metabelian Lie algebra . In
the current paper we introduce the notion of a metabelian Lie -algebra and
establish connections between metabelian Lie -algebras and special matrix
Lie algebras. We define the -localisation of a metabelian Lie
-algebra and the direct module extension of the Fitting's radical of
and show that these algebras lie in the universal closure of .Comment: 34 page
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
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
Anomalous asymmetry of magnetoresistance in NbSe single crystals
A pronounced asymmetry of magnetoresistance with respect to the magnetic
field direction is observed for NbSe crystals placed in a magnetic field
perpendicular to their conducting planes. It is shown that the effect persists
in a wide temperature range and manifests itself starting from a certain
magnetic induction value , which at K corresponds to the
transition to the quantum limit, i.to the state where the Landay level
splitting exceeds the temperature.Comment: 4 pages, 6 figures, to be appeared in JETP Let
Hall coefficient in heavy fermion metals
Experimental studies of the antiferromagnetic (AF) heavy fermion metal in a magnetic field indicate the presence of a jump in the Hall
coefficient at a magnetic-field tuned quantum state in the zero temperature
limit. This quantum state occurs at and induces the jump even
though the change of the magnetic field at is infinitesimal. We
investigate this by using the model of heavy electron liquid with the fermion
condensate. Within this model the jump takes place when the magnetic field
reaches the critical value at which the ordering temperature
of the AF transition vanishes. We show that at ,
this second order AF phase transition becomes the first order one, making the
corresponding quantum and thermal critical fluctuations vanish at the jump. At
and , the Gr\"uneisen ratio as a function of temperature
diverges. We demonstrate that both the divergence and the jump are determined
by the specific low temperature behavior of the entropy with , and are temperature independent
constants.Comment: 5 pages, 2 figure
Measurement of the decay form factors in the OKA experiment
A precise measurement of the vector and axial-vector form factors difference
in the decay is presented.
About 95K events of are selected in
the OKA experiment. The result is .
Both errors are smaller than in the previous measurements.Comment: 9 pages, 8 figure
Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions III: Tantalum Nuclei and Beam Momenta from +/-3 Gev/c to +/-15 Gev/c
We report on double-differential inclusive cross-sections of the production
of secondary protons, charged pions, and deuterons, in the interactions with a
5% nuclear interaction length thick stationary tantalum target, of proton and
pion beams with momentum from +/-3 GeV/c to +/-15 GeV/c. Results are given for
secondary particles with production angles between 20 and 125 degrees. They are
of particular relevance for the optimization of the design parameters of the
proton driver of a neutrino factory.Comment: 68 pages, 12 figures, corrections in v2: added 'HARP -CDP group' to
author name, corrected two typos in Table 4 (last two p values for 65-90
degrees were all 0.972
Information Support for the Implementation of Patriotic Education: Challenges of our Time
В статье анализируется необходимость информационного сопровождения для организации деятельности в сфере патриотического воспитания и применения всего комплекса инструментария по продвижению в социальных сетях и Интернет.The article analyzes the need for information support for the organization of activities in the field of patriotic education and the use of the entire range of tools for promotion in social networks and the Internet
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