321 research outputs found
Wavefunctional approach to the bilayer \nu =1 system and a possibility for a double non-chiral pseudospin liquid
We systematically discuss candidate wave functions for the ground state of
the bilayer \nu = 1 as the distance between the layers is varied. Those that
describe increased intralayer correlations at finite distance show a departure
from the superflid description for smaller distances. They may support finite
energy meron excitations and a dissipative collective mode in the place of the
Goldstone mode of the ordered phase i.e. describe a vortex metal phase, or
imply even an incompressible, pseudospin liquid, behavior. Therefore they
describe possible outcomes of quantum disordering at finite distance between
the layers. The vortex metal phase may show up in experiments in the presence
of disorder at lower temperatures and explain the observed "imperfect
superfluidity", and the pseudospin liquid phase may be the cause of the
thermally activated (gapped) behavior of the longitudinal and Hall resistances
at higher temperatures in counterflow experiments.Comment: 10 pages, 4 figure
Graphene membrane as a pressure gauge
Straining graphene results in the appearance of a pseudo-magnetic field which
alters its local electronic properties. Applying a pressure difference between
the two sides of the membrane causes it to bend/bulge resulting in a resistance
change. We find that the resistance changes linearly with pressure for bubbles
of small radius while the response becomes non-linear for bubbles that stretch
almost to the edges of the sample. This is explained as due to the strong
interference of propagating electronic modes inside the bubble. Our
calculations show that high gauge factors can be obtained in this way which
makes graphene a good candidate for pressure sensing.Comment: 5 pages, 4 figure
The Polumir granite: Addititional data on its origin
The Polumir granite is exposed on several localities due to erosion, and its chemical and mineral composition is presented in this paper. It is built of K-feldspar, plagioclase, myrmekite, metasomatic albite, biotite, muscovite and quartz, while apatite, magnetite, monazite, allanite and zircon are present as accessory minerals. According to its chemical and mineral composition and rock chemistry (trace and REE elements) the Polumir granite is leucocratic, sin-collisional, with S-type characteristics. It crystallized at temperature of about 650Ā°C and under pressure of 2-4 kbar. Results of isotope analyses (K-Ar method on biotites) indicate that the Polumir granite was formed during the Miocene (14-19 Ma) and it has undergone subsequent weak remobilization afterwards
Meron excitations in the nu =1 quantum Hall bilayer and the plasma analogy
We study meron quasiparticle excitations in the \nu = 1 quantum Hall bilayer.
Considering the well known single meron state, we introduce its effective form,
valid in the longdistance limit. That enables us to propose two (and more)
meron states in the same limit. Further, establishing a plasma analogy of the
(111) ground state, we find the impurities that play the role of merons and
derive meron charge distributions. Using the introduced meron constructions in
generalized (mixed) ground states and corresponding plasmas for arbitrary
distance between the layers, we calculate the interaction between the
construction implied impurities. We also find a correspondence between the
impurity interactions and meron interactions. This suggests a possible
explanation of the deconfinement of the merons recently observed in the
experiments.Comment: 5 pages, 3 figure
Effect of acute experimental aluminum poisoning on hematologic parameters
Having in mind the presence of aluminum in industry, as well as in households, we wanted to define changes in the number of erythrocytes and aluminum content in the plasma and erythrocytes following acute aluminum poisoning under experimental conditions. The experiment involved gerbils which received intraperitoneally aluminum chloride solution at a dose of 3.7g per kg of body mass. The experimental group was sacrificed after 24, 48, 72 and 96 hours from the beginning of the experiment by cardiac punction or by abdominal artery punction. The control group was treated with saline, only. The number of erythrocytes and hemoglobin concentration were considerably reduced with respect to the control group, most likely as the result of cell membrane changes and reduced life cycle of erythrocytes. During the experiment, aluminum content in the plasma was increased in the first and second day of the experiment, it started to decline on the third day, while on the fourth day it returned to its original value, which proves again the existence of a special mechanism of "clearance" of aluminum in plasma
Dipole representation of half-filled Landau level
We introduce a variant of dipole representation for composite fermions in a
half-filled Landau level, taking into account the symmetry under exchange of
particles and holes. This is implemented by a special constraint on composite
fermion and composite hole degree of freedom (of an enlarged space), that makes
the resulting composite particle, dipole, a symmetric object. We study an
effective Hamiltonian, that commutes with the constraint on the physical space,
and fulfills the requirement for boost invariance on the Fermi level. The
calculated Fermi liquid parameter F2 is in a good agreement with numerical
investigations in [Phys. Rev. Lett. 121, 147601 (2018)].Comment: 9 pages, 4 figure
Quadrature with multiple nodes, power orthogonality, and moment-preserving spline approximation, part ii
The paper deals with new contributions to the theory of the Gauss quadrature formulas with multiple nodes that are published after 2001, including numerical construction, error analysis and applications. The first part was published in Numerical analysis 2000, Vol. V, Quadrature and orthogonal polynomials (W. Gautschi, F. Marcellan, and L. Reichel, eds.) [J. Comput. Appl. Math. 127 (2001), no. 1-2, 267-286]
Quadrature with multiple nodes, power orthogonality, and moment-preserving spline approximation, part ii
The paper deals with new contributions to the theory of the Gauss quadrature formulas with multiple nodes that are published after 2001, including numerical construction, error analysis and applications. The first part was published in Numerical analysis 2000, Vol. V, Quadrature and orthogonal polynomials (W. Gautschi, F. Marcellan, and L. Reichel, eds.) [J. Comput. Appl. Math. 127 (2001), no. 1-2, 267-286]
Probabilistic analysis of voltage divider ratios
Tolerancija modernih otpornika obiÄno varira od 0.1% do 1 %. Sa probabilistiÄke taÄke glediÅ”ta to znaÄi da se odgovarajuÄi otpor može posmatrati kao sluÄajna promenljiva sa odgovarajuÄom funkcijom gustine raspodele verovatnoÄe (PDF). Dobijen je izraz za PDF za odnos prenosa dvo-otporniÄkog razdelniÄkog napona, kada je otporima u razdelniku dodeljena uniformna raspodela. Grafikoni dobijeni analitiÄkim izrazima, za razliÄite kombinacije nominalnih otpora i tolerancije dvaju otpornika, uporeÄeni su sa onima dobijenim numeriÄkim simulacijama. AsimetriÄni karakter dobijenog rezultantnog PDF-a, uzrokovan nelinearnoÅ”Äu funkcije razdelniÄkog kola, implicira da se nominalna, srednja i najverovatnija vrednost razdelniÄkog odnosa mogu razlikovati. Za normalnu raspodelu otpora u dvootporniÄkom razdelniku, analitiÄki pristup postaje složen, dok Monte Karlo simulacije lako daju grafikone naponskih odnosa PDF-a i izraÄunavaju vrednosti njihovih parametara.Tolerance of modern resistors typically ranges from 0.1% to 1%. From the probabilistic viewpoint, this is taken to mean that the corresponding resistance can be treated as a random variable, with an appropriate probability density function (PDF). We derive an expression for the PDF of a two-resistor voltage divider's transfer ratio, when the resistances in the divider are assigned uniform distributions. Plots of the obtained analytical expression, for various combinations of nominal resistances and tolerances of the two resistors, are compared to those produced by numerical (Monte Carlo) simulations. The asymmetrical character of the obtained resultant PDF, caused by non-linearity of the divider's circuit function, implies that the nominal, the mean and the most probable value of the divider's ratio can all differ. For normally distributed resistances in the two-resistor divider, analytical approach becomes complex, while Monte Carlo simulations readily provide the plots of voltage ratio PDFs and calculate the values of their parameters
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