2,693 research outputs found
Quantum critical behaviour of the plateau-insulator transition in the quantum Hall regime
High-field magnetotransport experiments provide an excellent tool to
investigate the plateau-insulator phase transition in the integral quantum Hall
effect. Here we review recent low-temperature high-field magnetotransport
studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs
quantum well. We find that the longitudinal resistivity near the
critical filling factor ~ 0.5 follows the universal scaling law
, where . The critical exponent equals ,
which indicates that the plateau-insulator transition falls in a non-Fermi
liquid universality class.Comment: 8 pages, accepted for publication in Proceedings of the Yamada
Conference LX on Research in High Magnetic Fields (August 16-19, 2006,
Sendai
Fractional charge in transport through a 1D correlated insulator of finite length
Transport through a one channel wire of length confined between two leads
is examined when the 1D electron system has an energy gap : induced by the interaction in charge mode (: charge velocity in the
wire). In spinless case the transformation of the leads electrons into the
charge density wave solitons of fractional charge entails a non-trivial low
energy crossover from the Fermi liquid behavior below the crossover energy to the insulator one with the
fractional charge in current vs. voltage, conductance vs. temperature, and in
shot noise. Similar behavior is predicted for the Mott insulator of filling
factor .Comment: 5 twocolumn pages in RevTex, no figure
Threshold features in transport through a 1D constriction
Suppression of electron current through a 1D channel of length
connecting two Fermi liquid reservoirs is studied taking into account the
Umklapp electron-electron interaction induced by a periodic potential. This
interaction causes Hubbard gaps for . In the perturbative
regime where ( charge velocity), and for small deviations
of the electron density from its commensurate values
can diverge with some exponent as voltage or temperature decreases above
, while it goes to zero below . This results
in a nonmonotonous behavior of the conductance.Comment: Final variant published in PRL, 79, 1714; minor correction
Broken symmetry, hyper-fermions, and universal conductance in transport through a fractional quantum Hall edge
We have found solution to a model of tunneling between a multi-channel Fermi
liquid reservoir and an edge of the principal fractional quantum Hall liquid
(FQHL) in the strong coupling limit. The solution explains how the absence of
the time-reversal symmetry at high energies due to chiral edge propagation
makes the universal two-terminal conductance of the FQHL fractionally quantized
and different from that of a 1D Tomonaga-Luttinger liquid wire, where a similar
model but preserving the time-reversal symmetry predicts unsuppressed
free-electron conductance.Comment: 5 twocolumn pages in RevTex, no figures, more explanations added, a
short version was published in JETP Letters, vol.74, 87 (2001
The moving boundary problem in the presence of a dipole magnetic field
An exact analytic solution is obtained for a uniformly expanding, neutral,
infinitely conducting plasma sphere in an external dipole magnetic field. The
electrodynamical aspects related to the radiation and transformation of energy
were considered as well. The results obtained can be used in analyzing the
recent experimental and simulation data.Comment: 17 pages, 1 figure, Submitted to J. Phys. A, Math. and Genera
PHARMACOECONOMICS OF APPLICATION OF HEPATOPROTECTORS IN THERAPY OF DRUG-INDUCED LIVER INJURY AFTER CHEMOTHERAPY
One of the major problems of modern oncology drug is liver damage, requiring additional costs for its treatment. The aim of our work was to study medical and economic efficiency of various schemes of hepatoprotective treatment of toxic liver damage. The paper presents the use of pharmacoeconomic studies in the treatment of hepatic drug-induced hepatitis, which occurs after chemotherapy in patients with Hodgkin's lymphoma. The study was conducted in the two comparison groups on a "cost - effectiveness". This method was chosen because it is in effect depending on the process (method), treatment was varied, as well as costs incurred. The unit of the effect of the number of days required for the relief of hepatic failure has been selected. Economic analysis of the work includes not only toxic hepatitis therapy, and treatment of any disease complications such as hepatic encephalopathy. The study revealed that the effectiveness of therapy increased 1.4 times and the economic costs were 51.8 % reduced with hepatoprotective drug "remaxol"
Is there a renormalization of the 1D conductance in Luttinger Liquid model?
Properties of 1D transport strongly depend on the proper choice of boundary
conditions. It has been frequently stated that the Luttinger Liquid (LL)
conductance is renormalized by the interaction as . To
contest this result I develop a model of 1D LL wire with the interaction
switching off at the infinities. Its solution shows that there is no
renormalization of the universal conductance while the electrons have a free
behavior in the source and drain reservoirs.Comment: 5 pages, RevTex 2.0, attempted repair of tex error
Interaction Constants and Dynamic Conductance of a Gated Wire
We show that the interaction constant governing the long-range
electron-electron interaction in a quantum wire coupled to two reservoirs and
capacitively coupled to a gate can be determined by a low frequency
measurement. We present a self-consistent, charge and current conserving theory
of the full conductance matrix. The collective excitation spectrum consists of
plasma modes with a relaxation rate which increases with the interaction
strength and is inversely proportional to the length of the wire. The
interaction parameter is determined by the first two coefficients of the
out-of-phase component of the dynamic conductance measured at the gate.Comment: 4 pages, LaTeX, 2 figure
EPIZOOTIOLOGICAL-EPIDEMIOLOGICAL SITUATION ON BRUCELLOSIS IN THE RUSSIAN FEDERATION IN 2016 AND PROGNOSIS FOR 2017
The article presents analysis of human and animal incidence of brucellosis in the Russian Federation in 2016. Epidemiological situation on brucellosis is characterized as unstable. Outlined has been the decrease in the number of newly diagnosed brucellosis cases in humans (15.8 %) against the background of the increasing trend for distress and deterioration of the epizootiological situation on brucellosis among the cattle in the regions with well-developed animal husbandry. Cases of group infection among the population in three constituent entities (Stavropol Region, Samara and Leningrad Regions) have been registered, which are of sporadic nature. According to the Federal Service for Veterinary and Phytosanitary Surveillance, mid-term forecast of epizootiological situation on brucellosis in Russia is unfavorable, which under the current trend constitutes a real risk of widespread brucellosis among the livestock in the regions of the Central and Volga Federal Districts. In 2017, we can predict maintaining of the unstable situation on the disease, morbidity rates among the population varying within the range of 340–370 cases
Negative local resistance caused by viscous electron backflow in graphene
Graphene hosts a unique electron system in which electron-phonon scattering
is extremely weak but electron-electron collisions are sufficiently frequent to
provide local equilibrium above liquid nitrogen temperature. Under these
conditions, electrons can behave as a viscous liquid and exhibit hydrodynamic
phenomena similar to classical liquids. Here we report strong evidence for this
transport regime. We find that doped graphene exhibits an anomalous (negative)
voltage drop near current injection contacts, which is attributed to the
formation of submicrometer-size whirlpools in the electron flow. The viscosity
of graphene's electron liquid is found to be ~0.1 m /s, an order of
magnitude larger than that of honey, in agreement with many-body theory. Our
work shows a possibility to study electron hydrodynamics using high quality
graphene
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