73 research outputs found
A Numerical Approach to Coulomb Gauge QCD
We calculate the ghost two-point function in Coulomb gauge QCD with a simple
model vacuum gluon wavefunction using Monte Carlo integration. This approach
extends the previous analytic studies of the ghost propagator with this ansatz,
where a ladder-rainbow expansion was unavoidable for calculating the path
integral over gluon field configurations. The new approach allows us to study
the possible critical behavior of the coupling constant, as well as the Coulomb
potential derived from the ghost dressing function. We demonstrate that IR
enhancement of the ghost correlator or Coulomb form factor fails to
quantitatively reproduce confinement using Gaussian vacuum wavefunctional
A model for QCD ground state with magnetic disorder
We explore an ansatz for the QCD vacuum in the Coulomb gauge that describes
gauge field fluctuations in presence of a weakly interacting gas of abelian
monopoles. Such magnetic disorder leads to long-range correlations which are
manifested through the area law for the Wilson loop. In particular we focus on
the role of the residual monopole-monopole interactions in providing the
mechanism for suppression of the gluon propagator at low-momenta which also
leads to low momentum enhancement in the ghost propagator.Comment: 6 pages, 1 figur
The Dynamics of Charges Induced by a Charged Particle Traversing a Dielectric Slab
We studied the dynamics of surfacea and wake charges induced by a charged
particle traversing a dielectric slab. It is shown that after the crossing of
the slab first boundary, the induced on the slab surface charge (image charge)
is transformed into the wake charge, which overflows to the second boundary
when the particle crosses it. It is also shown, that the polarization of the
slab is of an oscillatory nature, and the net induced charge in a slab remains
zero at all stages of the motion.Comment: 12 pages, 1 figur
Masses of ground and excited-state hadrons
We present the first Dyson-Schwinger equation calculation of the light hadron
spectrum that simultaneously correlates the masses of meson and baryon ground-
and excited-states within a single framework. At the core of our analysis is a
symmetry-preserving treatment of a vector-vector contact interaction. In
comparison with relevant quantities the
root-mean-square-relative-error/degree-of freedom is 13%. Notable amongst our
results is agreement between the computed baryon masses and the bare masses
employed in modern dynamical coupled-channels models of pion-nucleon reactions.
Our analysis provides insight into numerous aspects of baryon structure; e.g.,
relationships between the nucleon and Delta masses and those of the
dressed-quark and diquark correlations they contain.Comment: 25 pages, 7 figures, 4 table
Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive production
We present studies of single-spin asymmetries for neutral pion
electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV
polarized electrons from an unpolarized hydrogen target, using the CEBAF Large
Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator
Facility. A substantial amplitude has been measured in the
distribution of the cross section asymmetry as a function of the azimuthal
angle of the produced neutral pion. The dependence of this amplitude
on Bjorken and on the pion transverse momentum is extracted with
significantly higher precision than previous data and is compared to model
calculations.Comment: to be submitted PL
Strategies for continuous balancing in future power systems with high wind and solar shares
The use of wind power has grown strongly in recent years and is expected to continue to increase in the coming decades. Solar power is also expected to increase significantly. In a power system, a continuous balance is maintained between total production and demand. This balancing is currently mainly managed with conventional power plants, but with larger amounts of wind and solar power, other sources will also be needed. Interesting possibilities include continuous control of wind and solar power, battery storage, electric vehicles, hydrogen production, and other demand resources with flexibility potential. The aim of this article is to describe and compare the different challenges and future possibilities in six systems concerning how to keep a continuous balance in the future with significantly larger amounts of variable renewable power production. A realistic understanding of how these systems plan to handle continuous balancing is central to effectively develop a carbon-dioxide-free electricity system of the future. The systems included in the overview are the Nordic synchronous area, the island of Ireland, the Iberian Peninsula, Texas (ERCOT), the central European system, and Great Britain
Stereotype Level of Linguistic Concsiousnes: Socio- and Psycho-Linguistic Grounds
The linguistic consciousness is regarded as a multilevel system, its stereotype level being one of the structural bases. Applying a statistic analysis, the author justifies a reflex-driven nature of stereotype statements emphasizing their socio- and psycho-linguistic grounds. The paper describes a stereotype statement derivation, conditioned by language pragmatics, and focused on communication, which brings forth a need for standard. A stereotype statement development mechanism is based on a multiple repetition of a similar speech situation. As a result, communicative units used in such situations are perceived as steady correlated forms. Speech stereotypes, as many other standards, are less informative than non-stereotype forms. However, it does not undermine the significance of their studying, since they result from accumulation of socio-historical experience and knowledge.Given the mass communication, the process of identification and fixation of repeated common, emotional, and therefore, linguistic situations, is important and appropriate; and a list of such stereotype units can be subsequently used in the process of teaching foreign languages
Stereotype level of linguistic concsiousnes: socio- and psycholinguistic grounds
The linguistic consciousness is regarded as a multilevel system, its stereotype level being one of the structural bases. Applying a statistic analysis, the author justifies a reflex-driven nature of stereotype statements emphasizing their socio- and psycho-linguistic grounds. The paper describes a stereotype statement derivation, conditioned by language pragmatics, and focused on communication, which brings forth a need for standard. A stereotype statement development mechanism is based on a multiple repetition of a similar speech situation. As a result, communicative units used in such situations are perceived as steady correlated forms. Speech stereotypes, as many other standards, are less informative than non-stereotype forms. However, it does not undermine the significance of their studying, since they result from accumulation of socio-historical experience and knowledge.Given the mass communication, the process of identification and fixation of repeated common, emotional, and therefore, linguistic situations, is important and appropriate; and a list of such stereotype units can be subsequently used in the process of teaching foreign languages Язык имеет много пластов, один из них – стереотипный, являющийся составляющей структуры языкового (или «лингвокультурного») сознания, – подробно рассмотрен в данной статье. Автор на основании метода статистического анализа доказывает рефлекторную природу стереотипных высказываний и дает им социо- и психолингвистическое обоснование. Описывается процесс возникновения стереотипных выражений, обусловленнный прагматикой языка, его направленностью на общение, рождающей потребность в стандарте. Механизм образования стереотипных высказываний заключается в множественном повторении в однотипных речевых ситуациях, вследствие чего коммуникативные единицы, типизированно обслуживающие такие ситуации, воспринимаются как «связанные» устойчивые формулы. Речевые стереотипы, как и всякие стандарты, менее информативны, чем нестереотипные. Однако это не уменьшает значимости их изучения, ибо они являются результатом аккумуляции общественно-исторического опыта и знаний. В условиях массовой коммуникации выявление и фиксирование повторяющихся жизненных (бытовых и эмоциональных), а следовательно, и речевых ситуаций важно и целесообразно, так как наличие перечня/списка речевых единиц, обслуживающих подобные ситуации, поможет преподавателю-практику при обучении любому языку как иностранному
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