9,616 research outputs found
Gauge Transformations, BRST Cohomology and Wigner's Little Group
We discuss the (dual-)gauge transformations and BRST cohomology for the two
(1 + 1)-dimensional (2D) free Abelian one-form and four (3 + 1)-dimensional
(4D) free Abelian 2-form gauge theories by exploiting the (co-)BRST symmetries
(and their corresponding generators) for the Lagrangian densities of these
theories. For the 4D free 2-form gauge theory, we show that the changes on the
antisymmetric polarization tensor e^{\mu\nu} (k) due to (i) the (dual-)gauge
transformations corresponding to the internal symmetry group, and (ii) the
translation subgroup T(2) of the Wigner's little group, are connected with
each-other for the specific relationships among the parameters of these
transformation groups. In the language of BRST cohomology defined w.r.t. the
conserved and nilpotent (co-)BRST charges, the (dual-)gauge transformed states
turn out to be the sum of the original state and the (co-)BRST exact states. We
comment on (i) the quasi-topological nature of the 4D free 2-form gauge theory
from the degrees of freedom count on e^{\mu\nu} (k), and (ii) the Wigner's
little group and the BRST cohomology for the 2D one-form gauge theory {\it
vis-{\`a}-vis} our analysis for the 4D 2-form gauge theory.Comment: LaTeX file, 29 pages, misprints in (3.7), (3.8), (3.9), (3.13) and
(4.14)corrected and communicated to IJMPA as ``Erratum'
Geometrical Aspects Of BRST Cohomology In Augmented Superfield Formalism
In the framework of augmented superfield approach, we provide the geometrical
origin and interpretation for the nilpotent (anti-)BRST charges, (anti-)co-BRST
charges and a non-nilpotent bosonic charge. Together, these local and conserved
charges turn out to be responsible for a clear and cogent definition of the
Hodge decomposition theorem in the quantum Hilbert space of states. The above
charges owe their origin to the de Rham cohomological operators of differential
geometry which are found to be at the heart of some of the key concepts
associated with the interacting gauge theories. For our present review, we
choose the two -dimensional (2D) quantum electrodynamics (QED) as a
prototype field theoretical model to derive all the nilpotent symmetries for
all the fields present in this interacting gauge theory in the framework of
augmented superfield formulation and show that this theory is a {\it unique}
example of an interacting gauge theory which provides a tractable field
theoretical model for the Hodge theory.Comment: LaTeX file, 25 pages, Ref. [49] updated, correct page numbers of the
Journal are give
Nilpotent Symmetries For Matter Fields In Non-Abelian Gauge Theory: Augmented Superfield Formalism
In the framework of superfield approach to Becchi-Rouet-Stora-Tyutin (BRST)
formalism, the derivation of the (anti-)BRST nilpotent symmetries for the
matter fields, present in any arbitrary interacting gauge theory, has been a
long-standing problem. In our present investigation, the local, covariant,
continuous and off-shell nilpotent (anti-)BRST symmetry transformations for the
Dirac fields are derived in the framework of the augmented
superfield formulation where the four -dimensional (4D) interacting
non-Abelian gauge theory is considered on the six -dimensional
supermanifold parametrized by the four even spacetime coordinates and a
couple of odd elements ( and ) of the Grassmann algebra.
The requirement of the invariance of the matter (super)currents and the
horizontality condition on the (super)manifolds leads to the derivation of the
nilpotent symmetries for the matter fields as well as the gauge- and the
(anti-)ghost fields of the theory in the general scheme of the augmented
superfield formalism.Comment: LaTeX file, 16 pages, printing mistakes in the second paragraph of
`Introduction' corrected, a footnote added, these modifications submitted as
``erratum'' to IJMPA in the final for
Superfield Approach to (Non-)local Symmetries for One-Form Abelian Gauge Theory
We exploit the geometrical superfield formalism to derive the local,
covariant and continuous Becchi-Rouet-Stora-Tyutin (BRST) symmetry
transformations and the non-local, non-covariant and continuous dual-BRST
symmetry transformations for the free Abelian one-form gauge theory in four -dimensions (4D) of spacetime. Our discussion is carried out in the
framework of BRST invariant Lagrangian density for the above 4D theory in the
Feynman gauge. The geometrical origin and interpretation for the (dual-)BRST
charges (and the transformations they generate) are provided in the language of
translations of some superfields along the Grassmannian directions of the six
(-dimensional supermanifold parametrized by the four spacetime and two
Grassmannian variables.Comment: LaTeX file, 23 page
A new methodology called dice game optimizer for capacitor placement in distribution systems
Purpose. Shunt capacitors are installed in power system for compensating reactive power. Therefore, feeder capacity releases, voltage profile improves and power loss reduces. However, determination optimal location and size of capacitors in distributionsystems is a complex optimization problem. In order to determine the optimum size and location of the capacitor, an objective function which is generally defined based on capacitor installation costs and power losses should be minimized According to operational limitations. This paper offers a newly developed metaheuristic technique, named dice game optimizerto determine optimal size and location of capacitors in a distribution network. Dice game optimizer is a game based optimization technique that is based on the rules of the dice game.Π¦Π΅Π»Ρ. Π¨ΡΠ½ΡΠΈΡΡΡΡΠΈΠ΅ ΠΊΠΎΠ½Π΄Π΅Π½ΡΠ°ΡΠΎΡΡ Π² ΡΠ½Π΅ΡΠ³ΠΎΡΠΈΡΡΠ΅ΠΌΠ΅ ΡΡΡΠ°Π½Π°Π²Π»ΠΈΠ²Π°ΡΡΡΡ Π΄Π»Ρ ΠΊΠΎΠΌΠΏΠ΅Π½ΡΠ°ΡΠΈΠΈ ΡΠ΅Π°ΠΊΡΠΈΠ²Π½ΠΎΠΉ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ. Π‘Π»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎ, ΡΠ½ΠΈΠΆΠ°Π΅ΡΡΡ Π΅ΠΌΠΊΠΎΡΡΡ ΡΠΈΠ΄Π΅ΡΠ°, ΡΠ»ΡΡΡΠ°Π΅ΡΡΡ ΠΏΡΠΎΡΠΈΠ»Ρ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΡ ΠΈ ΡΠ½ΠΈΠΆΠ°ΡΡΡΡ ΠΏΠΎΡΠ΅ΡΠΈ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ. ΠΠ΄Π½Π°ΠΊΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΡΠΎΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΡ ΠΈ ΡΠ°Π·ΠΌΠ΅ΡΠ° ΠΊΠΎΠ½Π΄Π΅Π½ΡΠ°ΡΠΎΡΠΎΠ² Π² ΡΠΈΡΡΠ΅ΠΌΠ°Ρ
ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ»ΠΎΠΆΠ½ΠΎΠΉ Π·Π°Π΄Π°ΡΠ΅ΠΉ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ. Π§ΡΠΎΠ±Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΠΈΡΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΠΉ ΡΠ°Π·ΠΌΠ΅Ρ ΠΈ ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΠ΅ ΠΊΠΎΠ½Π΄Π΅Π½ΡΠ°ΡΠΎΡΠ°, ΡΠ΅Π»Π΅Π²ΡΡ ΡΡΠ½ΠΊΡΠΈΡ, ΠΊΠΎΡΠΎΡΠ°Ρ ΠΎΠ±ΡΡΠ½ΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ Π·Π°ΡΡΠ°Ρ Π½Π° ΡΡΡΠ°Π½ΠΎΠ²ΠΊΡ ΠΊΠΎΠ½Π΄Π΅Π½ΡΠ°ΡΠΎΡΠ° ΠΈ ΠΏΠΎΡΠ΅ΡΡ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ, ΡΠ»Π΅Π΄ΡΠ΅Ρ ΠΌΠΈΠ½ΠΈΠΌΠΈΠ·ΠΈΡΠΎΠ²Π°ΡΡ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΡΠΊΡΠΏΠ»ΡΠ°ΡΠ°ΡΠΈΠΎΠ½Π½ΡΠΌΠΈ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΈΡΠΌΠΈ. ΠΠ°Π½Π½Π°Ρ ΡΡΠ°ΡΡΡ ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅Ρ Π½Π΅Π΄Π°Π²Π½ΠΎ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠ°Π½Π½ΡΠΉ ΠΌΠ΅ΡΠ°ΡΠ²ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄, Π½Π°Π·ΡΠ²Π°Π΅ΠΌΡΠΉ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΎΡΠΎΠΌ ΠΈΠ³ΡΡ Π² ΠΊΠΎΡΡΠΈ, Π΄Π»Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·ΠΌΠ΅ΡΠ° ΠΈ ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΡ ΠΊΠΎΠ½Π΄Π΅Π½ΡΠ°ΡΠΎΡΠΎΠ² Π² ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠ΅ΡΠΈ. ΠΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΎΡ ΠΈΠ³ΡΡ Π² ΠΊΠΎΡΡΠΈ β ΡΡΠΎ ΠΈΠ³ΡΠΎΠ²ΠΎΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΠΉ Π½Π° ΠΏΡΠ°Π²ΠΈΠ»Π°Ρ
ΠΈΠ³ΡΡ Π² ΠΊΠΎΡΡΠΈ
Comments on the dual-BRST symmetry
In view of a raging controversy on the topic of
dual-Becchi-Rouet-Stora-Tyutin (dual-BRST/co-BRST) and anti-co-BRST symmetry
transformations in the context of four (3+1)-dimensional (4D) Abelian 2-form
and 2D (non-)Abelian 1-form gauge theories, we attempt, in our present short
note, to settle the dust by taking the help of mathematics of differential
geometry, connected with the Hodge theory, which was the original motivation
for the nomenclature of "dual-BRST symmetry" in our earlier set of works. It
has been claimed, in a recent set of papers, that the co-BRST symmetries are
not independent of the BRST symmetries. We show that the BRST and co-BRST
symmetries are independent symmetries in the same fashion as the exterior and
co-exterior derivatives are independent entities belonging to the set of de
Rham cohomological operators of differential geometry.Comment: LaTeX file, 6 pages, journal versio
Fault diagnosis of rotor using EMD thresholding-based de-noising combined with probabilistic neural network
De-noising of signal processing is crucial for fault diagnosis in order to successfully conduct feature extraction and is an efficient method for accurate determination of cause. In this paper, the empirical mode decomposition (EMD) thresholding-based de-noising method and probabilistic neural network (PNN) are respectively used in the de-noising of the vibration signal and rotor fault diagnosis and compared with wavelet thresholding-based de-noising technology and back propagation neural network (BPNN). The results show that the clear iterative EMD interval thresholding performs better than wavelet thresholding in the de-noising of the vibration signal, and avoids the determination of wavelet basis and decomposition level. In addition, the PNN created by feature samples does not require training and has a higher accuracy than BPNN
Multiple model MIMO predictive control for variable speed variable pitch wind turbines
Abstract-A multivariable control strategy based on model predictive control techniques for the control of variable speed variable pitch wind turbines is proposed. The proposed control strategy is described for the whole operating region of the wind turbine (both partial and full load regimes). Pitch angle and generator torque are controlled simultaneously to maximize energy capture, mitigate drive train transient loads and smooth the power generated while reducing the pitch actuator activity. This has the effect of improving the efficiency and the power quality of the electrical power generated, and of increasing the life time of the system's mechanical parts. Furthermore, safe and acceptable operation of the system is guaranteed by incorporating most of the constraints on the physical variables of the WECS in the controller design. In order to cope with nonlinearities in the WECS and continuous variations in the operating point, a multiple model predictive controller is suggested which provides near optimal performance throughout the whole operating region
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