5,843 research outputs found
N=2 supersymmetric Yang-Mills theory and the superparticle: twistor transform and kappa-symmetry
Lagrangian and Hamiltonian dynamics of de Azcarraga-Lukierski N=2 massive
superparticle is considered in the framework of twistor-like Lorentz-harmonic
approach. The emphasis is on the study of the interaction with external Abelian
gauge superfield. The requirement of preservation of all gauge symmetries of
the free model including kappa-symmetry yields correct expressions for the
superfield strength constraints and determines the form of nonminimal
interaction. We also show that for de Azcarraga-Lukierski N=2 massive
superparticle the pullback of field strength 2-superform to the superworld line
is not integrable in contrast to the massless superparticle.Comment: 16 pages, LaTe
Gauge symmetries of strings in supertwistor space
Recently we have considered supertwistor reformulation of the D=4 N=1,2
superstring action that comprises Newman-Penrose dyad components and is
classically equivalent to the Green-Schwarz one. It was shown that in the
covariant kappa-symmetry gauge the supertwistor representation of the string
action simplifies. Here we analyze its Hamiltonian formulation, classify the
constraints on the phase-space variables, and find the covariant set of
generators of the gauge symmetries. Quantum symmetries of the supertwistor
representation of the string action are examined applying the world-sheet CFT
technique. Considered are various generalizations of the model from the
perspective of their possible relation to known twistor superstring models.Comment: 17 pages, LaTeX; v.2 minor changes in the text, references added,
misprints correcte
AdS_4 x CP^3 superstring and D=3 N=6 superconformal symmetry
Motivated by the isomorphism between osp(4|6) superalgebra and D=3 N=6
superconformal algebra we consider the superstring action on the AdS_4 x CP^3
background parametrized by D=3 N=6 super-Poincare and CP^3 coordinates
supplemented by the coordinates corresponoding to dilatation and superconformal
generators. It is also discussed the relation between the degeneracy of
fermionic equations of motion and the action kappa-invariance in the framework
of the supercoset approach.Comment: revtex, 12 pages. Version accepted to Phys. Rev. D; v4 corrected
misprints in Eqs.(65), (71); v5 corrected discussion of Z_4 grading on page
The aerodynamics of a jet of particles in a channel
The main cause for dust discharge is ejection, i.e. formation of directional air flows in a stream of a bulk material due to the dynamic interaction of bombarding particles with air. Discovery of induced air flow occurrence regularities enables both forecasting the level of air pollutions with aerosol emission and choosing the optimum engineering solutions of air containment and dedusting. So far we have studied solid particles flowing in a chute and a jet of loose matter. Both situations represent extreme cases of the more general problem of material flowing through a duct with different distances between flow boundaries and duct walls. Without detriment to generality of the problem we shall consider a flat flow limited by vertical walls
Aerodynamic properties of particles in the gravitational flow of a chuted bulk material
Chutes are a linking element of transportation lines used for transfers of reprocessed materials from one transporting group or equipment to another. The mode of the chuted material motion and the nature of the associated aerodynamic processes are determined by the aggregate physical and mechanical properties of the material being transferred and structural design of chutes. Structurally chutes are subdivided into prismatic, cylindrical and pyramid-shaped (bin) chutes by shape and into vertical, tip and kinked chutes by the bottom slope angle. The most common in practice are tip chutes of a prismatic or a pyramid shape. The purpose of this work was the study of particle movement of granular materials in the sloping chute. In the result of the research, we revealed the following
Study of the properties of Plessey's electrocardiographic capacitive electrodes for portable systems
Cardiac diseases are still most widely spread in all regions of the world. And more and more devices are invented to satisfy increasing requirements of the patients. One of the perspective technologies in cardiac diagnostics is capacitive sensing ECG electrodes
Finite Temperature QCD with Two Flavors of Non-perturbatively Improved Wilson Fermions
We study QCD with two flavors of non-perturbatively improved Wilson fermions
at finite temperature on the lattice. We determine the transition
temperature at lattice spacings as small as fm, and study string
breaking below the finite temperature transition. We find that the static
potential can be fitted by a two-state ansatz, including a string state and a
two-meson state. We investigate the role of Abelian monopoles at finite
temperature.Comment: 29 pages, 22 figures, Late
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