102 research outputs found
Quantum criticality, particle-hole symmetry, and duality of the plateau-insulator transition in the quantum Hall regime
We report new experimental data on the plateau-insulator transition in the
quantum Hall regime, taken from a low mobility InGaAs/InP heterostructure. By
employing the fundamental symmetries of the quantum transport problem we are
able to disentangle the universal quantum critical aspects of the
magnetoresistance data (critical indices and scaling functions) and the sample
dependent aspects due to macroscopic inhomogeneities. Our new results and
methodology indicate that the previously established experimental value for the
critical index (kappa = 0.42) resulted from an admixture of both universal and
sample dependent behavior. A novel, non-Fermi liquid value is found (kappa =
0.57) along with the leading corrections to scaling. The statement of
self-duality under the Chern Simons flux attachment transformation is verified.Comment: 4 pages, 2 figure
New Insights into the Plateau-Insulator Transition in the Quantum Hall Regime
We have measured the quantum critical behavior of the plateau-insulator (PI)
transition in a low-mobility InGaAs/GaAs quantum well. The longitudinal
resistivity measured for two different values of the electron density follows
an exponential law, from which we extract critical exponents kappa = 0.54 and
0.58, in good agreement with the value (kappa = 0.57) previously obtained for
an InGaAs/InP heterostructure. This provides evidence for a non-Fermi liquid
critical exponent. By reversing the direction of the magnetic field we find
that the averaged Hall resistance remains quantized at the plateau value h/e^2
through the PI transition. From the deviations of the Hall resistance from the
quantized value, we obtain the corrections to scaling.Comment: accepted proceedings of EP2DS-15 (to be published in Physica E
The effect of carrier density gradients on magnetotransport data measured in Hall bar geometry
We have measured magnetotransport of the two-dimensional electron gas in a
Hall bar geometry in the presence of small carrier density gradients. We find
that the longitudinal resistances measured at both sides of the Hall bar
interchange by reversing the polarity of the magnetic field. We offer a simple
explanation for this effect and discuss implications for extracting
conductivity flow diagrams of the integer quantum Hall effect.Comment: 7 pages, 8 figure
The effects of macroscopic inhomogeneities on the magneto transport properties of the electron gas in two dimensions
In experiments on electron transport the macroscopic inhomogeneities in the
sample play a fundamental role. In this paper and a subsequent one we introduce
and develop a general formalism that captures the principal features of sample
inhomogeneities (density gradients, contact misalignments) in the magneto
resistance data taken from low mobility heterostructures. We present detailed
assessments and experimental investigations of the different regimes of
physical interest, notably the regime of semiclassical transport at weak
magnetic fields, the plateau-plateau transitions as well as the
plateau-insulator transition that generally occurs at much stronger values of
the external field only.
It is shown that the semiclassical regime at weak fields plays an integral
role in the general understanding of the experiments on the quantum Hall
regime. The results of this paper clearly indicate that the plateau-plateau
transitions, unlike the the plateau-insulator transition, are fundamentally
affected by the presence of sample inhomogeneities. We propose a universal
scaling result for the magneto resistance parameters. This result facilitates,
amongst many other things, a detailed understanding of the difficulties
associated with the experimental methodology of H.P. Wei et.al in extracting
the quantum critical behavior of the electron gas from the transport
measurements conducted on the plateau-plateau transitions.Comment: 20 pages, 9 figure
Modeling electrolytically top gated graphene
We investigate doping of a single-layer graphene in the presence of
electrolytic top gating. The interfacial phenomena is modeled using a modified
Poisson-Boltzmann equation for an aqueous solution of simple salt. We
demonstrate both the sensitivity of graphene's doping levels to the salt
concentration and the importance of quantum capacitance that arises due to the
smallness of the Debye screening length in the electrolyte.Comment: 7 pages, including 4 figures, submitted to Nanoscale Research Letters
for a special issue related to the NGC 2009 conference
(http://asdn.net/ngc2009/index.shtml
High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices
Cyclotron motion of charge carriers in metals and semiconductors leads to Landau quantization and magneto-oscillatory behavior in their properties. Cryogenic temperatures are usually required to observe these oscillations. We show that graphene superlattices support a different type of quantum oscillations that do not rely on Landau quantization. The oscillations are extremely robust and persist well above room temperature in magnetic fields of only a few T. We attribute this phenomenon to repetitive changes in the electronic structure of superlattices such that charge carriers experience effectively no magnetic field at simple fractions of the flux quantum per superlattice unit cell. Our work points at unexplored physics in Hofstadter butterfly systems at high temperatures
Exact eigenstate analysis of finite-frequency conductivity in graphene
We employ the exact eigenstate basis formalism to study electrical
conductivity in graphene, in the presence of short-range diagonal disorder and
inter-valley scattering. We find that for disorder strength, 5, the
density of states is flat. We, then, make connection, using the MRG approach,
with the work of Abrahams \textit{et al.} and find a very good agreement for
disorder strength, = 5. For low disorder strength, = 2, we plot the
energy-resolved current matrix elements squared for different locations of the
Fermi energy from the band centre. We find that the states close to the band
centre are more extended and falls of nearly as as we move away
from the band centre. Further studies of current matrix elements versus
disorder strength suggests a cross-over from weakly localized to a very weakly
localized system. We calculate conductivity using Kubo Greenwood formula and
show that, for low disorder strength, conductivity is in a good qualitative
agreement with the experiments, even for the on-site disorder. The intensity
plots of the eigenstates also reveal clear signatures of puddle formation for
very small carrier concentration. We also make comparison with square lattice
and find that graphene is more easily localized when subject to disorder.Comment: 11 pages,15 figure
ЀОзОŃĐ”ŃĐșОД ĐŒĐ”ŃĐŸĐŽŃ ŃДабОлОŃĐ°ŃОО паŃĐžĐ”ĐœŃĐŸĐČ Ń ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·ĐŸĐŒ: ĐœĐ°ŃĐșĐŸĐŒĐ”ŃŃĐžŃĐ”ŃĐșĐžĐč Đ°ĐœĐ°Đ»ĐžĐ· ĐŽĐŸĐșĐ°Đ·Đ°ŃДлŃĐœŃŃ ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč
Relevance. A rise in the life expectancy of the planetâs population, lack of exercise and growth in the number of people suffering from overweight lead to an increase in the number of patients suffering from diseases of the musculoskeletal system, including osteoarthritis. Given the absence of specific pharmacological treatment of osteoarthritis, as well as the increase in the number of patients with co-morbid pathology, it became necessary to search for the proven technologies of physical and rehabilitation medicine (PRM). The purpose of the study was to identify the most effective PRM technologies in the treatment of patients with osteoarthritis and to formulate recommendations on their use for practitioners, based on the proof obtained through the analysis of evidence-based high quality studies on the application of PRM technology. Materials and Methods. Over the past decade, there has been a significant increase in the number of studies on non-pharmacological methods of osteoarthritis treatment. The most studied of the PRM technologies with the proven effect were the following: physical exercises combined with traditional healthy gymnastics, acupuncture, peloid therapy, balneo therapy, as well as low-frequency electrotherapy, ultrasound therapy and infrared laser therapy. Conclusion. The use of PRM technologies in the treatment of patients with osteoarthritis should be based on the results of high-quality randomized controlled clinical trials which serve as the basis for the development of clinical recommendations. The process of the obtained data analysis should be conducted on the regular basis.ĐĐșŃŃĐ°Đ»ŃĐœĐŸŃŃŃ. ĐŁĐČДлОŃĐ”ĐœĐžĐ” ĐżŃĐŸĐŽĐŸĐ»Đ¶ĐžŃДлŃĐœĐŸŃŃĐž Đ¶ĐžĐ·ĐœĐž ĐœĐ°ŃĐ”Đ»Đ”ĐœĐžŃ ĐżĐ»Đ°ĐœĐ”ŃŃ, ĐłĐžĐżĐŸĐŽĐžĐœĐ°ĐŒĐžŃ Đž ŃĐŸŃŃ ŃĐžŃла Đ»ŃĐŽĐ”Đč Ń ĐžĐ·Đ±ŃŃĐŸŃĐœĐŸĐč ĐŒĐ°ŃŃĐŸĐč ŃДла ĐżŃĐžĐČĐŸĐŽŃŃ Đș ŃĐČДлОŃĐ”ĐœĐžŃ ĐșĐŸĐ»ĐžŃĐ”ŃŃĐČĐ° паŃĐžĐ”ĐœŃĐŸĐČ, ŃŃŃĐ°ĐŽĐ°ŃŃĐžŃ
Đ·Đ°Đ±ĐŸĐ»Đ”ĐČĐ°ĐœĐžŃĐŒĐž ĐŸĐżĐŸŃĐœĐŸ-ĐŽĐČОгаŃДлŃĐœĐŸĐłĐŸ аппаŃĐ°ŃĐ°, ĐČ ŃĐŸĐŒ ŃĐžŃлД ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·ĐŸĐŒ. ĐŁŃĐžŃŃĐČĐ°Ń ĐŸŃŃŃŃŃŃĐČОД ŃпДŃĐžŃĐžŃĐ”ŃĐșĐŸĐłĐŸ ŃĐ°ŃĐŒĐ°ĐșĐŸĐ»ĐŸĐłĐžŃĐ”ŃĐșĐŸĐłĐŸ лДŃĐ”ĐœĐžŃ ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·Đ°, Đ° ŃĐ°ĐșжД ŃĐŸŃŃ ŃĐžŃла паŃĐžĐ”ĐœŃĐŸĐČ Ń ĐșĐŸĐŒĐŸŃĐ±ĐžĐŽĐœĐŸĐč паŃĐŸĐ»ĐŸĐłĐžĐ”Đč, ĐČĐŸĐ·ĐœĐžĐșла ĐœĐ”ĐŸĐ±Ń
ĐŸĐŽĐžĐŒĐŸŃŃŃ ĐżĐŸĐžŃĐșĐ° ĐŽĐŸĐșĐ°Đ·Đ°ĐœĐœŃŃ
ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐč ŃОзОŃĐ”ŃĐșĐŸĐč Đž ŃДабОлОŃĐ°ŃĐžĐŸĐœĐœĐŸĐč ĐŒĐ”ĐŽĐžŃĐžĐœŃ (ЀРĐ). ĐŠĐ”Đ»Ń ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžŃ â ĐČŃŃĐČĐžŃŃ ĐœĐ°ĐžĐ±ĐŸĐ»Đ”Đ” ŃŃŃĐ”ĐșŃĐžĐČĐœŃĐ” ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐž ЀРРĐČ Đ»Đ”ŃĐ”ĐœĐžĐž паŃĐžĐ”ĐœŃĐŸĐČ Ń ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·ĐŸĐŒ Đž ŃŃĐŸŃĐŒŃлОŃĐŸĐČĐ°ŃŃ ŃĐ”ĐșĐŸĐŒĐ”ĐœĐŽĐ°ŃОО ĐżĐŸ ĐžŃ
ĐżŃĐžĐŒĐ”ĐœĐ”ĐœĐžŃ ĐŽĐ»Ń ĐżŃĐ°ĐșŃĐžŃĐ”ŃĐșĐžŃ
ĐČŃĐ°ŃĐ”Đč, ĐŸŃĐœĐŸĐČĐ°ĐœĐœŃĐ” ĐœĐ° ĐŽĐŸĐșĐ°Đ·Đ°ŃДлŃŃŃĐČĐ°Ń
, ĐżĐŸĐ»ŃŃĐ”ĐœĐœŃŃ
ĐČ Ń
ĐŸĐŽĐ” Đ°ĐœĐ°Đ»ĐžĐ·Đ° баз ĐŽĐŸĐșĐ°Đ·Đ°ŃДлŃĐœŃŃ
ĐŽĐŸĐ±ŃĐŸĐșĐ°ŃĐ”ŃŃĐČĐ”ĐœĐœŃŃ
ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč ĐżĐŸ ĐżŃĐžĐŒĐ”ĐœĐ”ĐœĐžŃ ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐž ЀРĐ. ĐĐ°ŃĐ”ŃОал Đž ĐŒĐ”ŃĐŸĐŽŃ. ĐĄŃĐ°ŃŃŃ ĐŸŃĐœĐŸĐČĐ°ĐœĐ° ĐœĐ° ŃДзŃĐ»ŃŃĐ°ŃĐ°Ń
ĐœĐ°ŃĐșĐŸĐŒĐ”ŃŃĐžŃĐ”ŃĐșĐŸĐłĐŸ Đ°ĐœĐ°Đ»ĐžĐ·Đ° 1183 ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč, ĐżŃĐŸĐČĐ”ĐŽĐ”ĐœĐœŃŃ
Ń 2000 ĐżĐŸ 2019 Đł., ĐżĐŸŃĐČŃŃĐ”ĐœĐœŃŃ
ĐžŃĐżĐŸĐ»ŃĐ·ĐŸĐČĐ°ĐœĐžŃ ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐč ЀРРĐČ Đ»Đ”ŃĐ”ĐœĐžĐž паŃĐžĐ”ĐœŃĐŸĐČ Ń ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·ĐŸĐŒ. Đ ĐžŃĐŸĐłĐŸĐČŃĐč Đ°ĐœĐ°Đ»ĐžĐ· ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐč ЀРРпŃĐ”ĐžĐŒŃŃĐ”ŃŃĐČĐ”ĐœĐœĐŸ ĐČĐșĐ»ŃŃĐ”ĐœŃ Đ·Đ°ŃŃĐ±Đ”Đ¶ĐœŃĐ” ĐșĐ»ĐžĐœĐžŃĐ”ŃĐșОД ŃĐ”ĐșĐŸĐŒĐ”ĐœĐŽĐ°ŃОО/ŃŃĐșĐŸĐČĐŸĐŽŃŃĐČĐ° (practice guidelines), ŃĐžŃŃĐ”ĐŒĐ°ŃĐžŃĐ”ŃĐșОД ĐŸĐ±Đ·ĐŸŃŃ (ĐĄĐ), ĐŒĐ”ŃĐ°Đ°ĐœĐ°Đ»ĐžĐ·Ń Đ ĐĐ, ĐŽĐ°ĐœĐœŃĐ” ĐŸŃЎДлŃĐœŃŃ
Đ ĐĐ ĐœĐ° Đ°ĐœĐłĐ»ĐžĐčŃĐșĐŸĐŒ ОлО ŃŃŃŃĐșĐŸĐŒ ŃĐ·ŃĐșĐ°Ń
, ĐŸŃĐ”ĐœĐ”ĐœĐœŃĐ” ĐœĐ° 6 Đ±Đ°Đ»Đ»ĐŸĐČ Đž ĐČŃŃĐ” ĐżĐŸ ŃĐșалД PEDro. Đ ŃДзŃĐ»ŃŃĐ°ŃĐ” ĐœĐ°ŃĐșĐŸĐŒĐ”ŃŃĐžŃĐ”ŃĐșĐŸĐłĐŸ Đ°ĐœĐ°Đ»ĐžĐ·Đ° бŃлО ŃŃĐŸŃĐŒĐžŃĐŸĐČĐ°ĐœŃ ŃаблОŃŃ ĐŽĐŸĐșĐ°Đ·Đ°ŃДлŃŃŃĐČ Ń ĐżŃĐžŃĐČĐŸĐ”ĐœĐžĐ”ĐŒ ĐșĐ°Đ¶ĐŽĐŸĐč ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐž ЀРРŃŃĐŸĐČĐœŃ ŃбДЎОŃДлŃĐœĐŸŃŃĐž ĐŽĐŸĐșĐ°Đ·Đ°ŃДлŃŃŃĐČ Đž ĐșлаŃŃĐ° ŃĐ”ĐșĐŸĐŒĐ”ĐœĐŽĐ°ŃĐžĐč ĐżĐŸ GRADE ĐČ ŃĐŸĐŸŃĐČĐ”ŃŃŃĐČОО Ń ĐĐĐĄĐą Đ 56034-2014. РДзŃĐ»ŃŃĐ°ŃŃ. ĐĐ° ĐżĐŸŃĐ»Đ”ĐŽĐœĐ”Đ” ĐŽĐ”ŃŃŃОлДŃОД ĐżŃĐŸĐžĐ·ĐŸŃДл ĐŸŃŃŃĐžĐŒŃĐč ŃĐŸŃŃ ĐșĐŸĐ»ĐžŃĐ”ŃŃĐČĐ° ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč, ĐżĐŸŃĐČŃŃĐ”ĐœĐœŃŃ
ĐœĐ”ŃĐ°ŃĐŒĐ°ĐșĐŸĐ»ĐŸĐłĐžŃĐ”ŃĐșĐžĐŒ ĐŒĐ”ŃĐŸĐŽĐ°ĐŒ лДŃĐ”ĐœĐžŃ ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·Đ°. ĐĐ°ĐžĐ±ĐŸĐ»Đ”Đ” ОзŃŃĐ”ĐœĐœŃĐŒĐž Оз ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐč ЀРĐ, ĐșĐŸŃĐŸŃŃĐ” ĐžĐŒĐ”ŃŃ ĐŽĐŸĐșĐ°Đ·Đ°ĐœĐœŃĐč ŃŃŃĐ”ĐșŃ, ŃĐČĐ»ŃŃŃŃŃ ŃОзОŃĐ”ŃĐșОД ŃĐżŃĐ°Đ¶ĐœĐ”ĐœĐžŃ ĐČ ŃĐŸŃĐ”ŃĐ°ĐœĐžĐž Ń ŃŃĐ°ĐŽĐžŃĐžĐŸĐœĐœĐŸĐč ĐŸĐ·ĐŽĐŸŃĐŸĐČĐžŃДлŃĐœĐŸĐč ĐłĐžĐŒĐœĐ°ŃŃĐžĐșĐŸĐč Đž Đ°ĐșŃĐżŃĐœĐșŃŃŃĐŸĐč, ĐżĐ”Đ»ĐŸĐžĐŽĐŸŃĐ”ŃапОŃ, балŃĐœĐ”ĐŸŃĐ”ŃапОŃ, Đ° ŃĐ°ĐșжД ĐœĐžĐ·ĐșĐŸŃĐ°ŃŃĐŸŃĐœĐ°Ń ŃлДĐșŃŃĐŸŃĐ”ŃапОŃ, ŃĐ»ŃŃŃĐ°Đ·ĐČŃĐșĐŸĐČĐ°Ń ŃĐ”ŃĐ°ĐżĐžŃ Đž ĐžĐœŃŃĐ°ĐșŃĐ°ŃĐœĐ°Ń Đ»Đ°Đ·Đ”ŃĐŸŃĐ”ŃапОŃ. ĐĐ°ĐșĐ»ŃŃĐ”ĐœĐžĐ”. ĐŃĐżĐŸĐ»ŃĐ·ĐŸĐČĐ°ĐœĐžĐ” ŃĐ”Ń
ĐœĐŸĐ»ĐŸĐłĐžĐč ЀРРĐČ Đ»Đ”ŃĐ”ĐœĐžĐž паŃĐžĐ”ĐœŃĐŸĐČ Ń ĐŸŃŃĐ”ĐŸĐ°ŃŃŃĐŸĐ·ĐŸĐŒ ĐŽĐŸĐ»Đ¶ĐœĐŸ бŃŃŃ ĐŸŃĐœĐŸĐČĐ°ĐœĐŸ ĐœĐ° ŃДзŃĐ»ŃŃĐ°ŃĐ°Ń
ĐșĐ°ŃĐ”ŃŃĐČĐ”ĐœĐœŃŃ
ŃĐ°ĐœĐŽĐŸĐŒĐžĐ·ĐžŃĐŸĐČĐ°ĐœĐœŃŃ
ĐșĐŸĐœŃŃĐŸĐ»ĐžŃŃĐ”ĐŒŃŃ
ĐșĐ»ĐžĐœĐžŃĐ”ŃĐșĐžŃ
ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč, ĐșĐŸŃĐŸŃŃĐ” ŃĐ»ŃĐ¶Đ°Ń ĐŸŃĐœĐŸĐČĐŸĐč ĐŽĐ»Ń ŃĐ°Đ·ŃĐ°Đ±ĐŸŃĐșĐž ĐșĐ»ĐžĐœĐžŃĐ”ŃĐșĐžŃ
ŃĐ”ĐșĐŸĐŒĐ”ĐœĐŽĐ°ŃĐžĐč. ĐĐœĐ°Đ»ĐžĐ· ĐŽĐ°ĐœĐœŃŃ
ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐč ĐŽĐŸĐ»Đ¶Đ”Đœ ĐœĐŸŃĐžŃŃ ŃДгŃĐ»ŃŃĐœŃĐč Ń
Đ°ŃĐ°ĐșŃĐ”Ń
Scattering theory and ground-state energy of Dirac fermions in graphene with two Coulomb impurities
We study the physics of Dirac fermions in a gapped graphene monolayer containing two Coulomb impurities. For the case of equal impurity charges, we discuss the ground-state energy using the linear combination of atomic orbitals (LCAO) approach. For opposite charges of the Coulomb centers, an electric dipole potential results at large distances. We provide a nonperturbative analysis of the corresponding low-energy scattering problem
Measurement of the cross section for isolated-photon plus jet production in pp collisions at âs=13 TeV using the ATLAS detector
The dynamics of isolated-photon production in association with a jet in protonâproton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fbâ1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photonâjet invariant mass and the scattering angle in the photonâjet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements
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