11,285 research outputs found
Conversion of second class constraints by deformation of Lagrangian local symmetries
For a theory with first and second class constraints, we propose a procedure
for conversion of second class constraints based on deformation the structure
of local symmetries of the Lagrangian formulation. It does not require
extension or reduction of configuration space of the theory. We give examples
in which the initial formulation implies a non linear realization of some
global symmetries, therefore is not convenient. The conversion reveals hidden
symmetry presented in the theory. The extra gauge freedom of conversed version
is used to search for a parameterization which linearizes the equations of
motion. We apply the above procedure to membrane theory (in the formulation
with world-volume metric). In the resulting version, all the metric components
are gauge degrees of freedom. The above procedure works also in a theory with
only second class constraints presented. As an examples, we discuss arbitrary
dynamical system of classical mechanics subject to kinematic constraints,
O(N)-invariant nonlinear sigma-model, and the theory of massive vector field
with Maxwell-Proca Lagrangian.Comment: 23 pages, misprints corrected. Slightly compactified version is
published in Phys. Lett. B 646 (2007) 4
Coding theorems for hybrid channels. II
The present work continues investigation of the capacities of measurement
(quantum-classical) channels in the most general setting, initiated
in~\cite{HCT}. The proof of coding theorems is given for the classical capacity
and entanglement-assisted classical capacity of the measurement channel with
arbitrary output alphabet, without assuming that the channel is given by a
bounded operator-valued density.Comment: 15 pages, one figur
Improving regional regulatory platform tools for the development of small and medium businesses
Introduction. Taking into account the priorities of the state policy in the field of economic and innovative development of the Perm region, assessment of the regional potential of the digital economy, the strategic importance of economic activities implemented by SMEs for the economy of the region and the country as a whole, the actual impact of the norms on the instruments of development of small and medium-sized enterprises in the Perm region is assessed. The purpose of this study is to improve the regional regulatory platform of tools for the development of small and medium-sized businesses in the Perm region in order to gain the status of an investment-attractive region in the digital economy of the Russian Federation, taking into account the Strategy of the information society in the Russian Federation, which will ultimately contribute to the development of e-business in the Perm region, rehabilitation and competitiveness of the economy of the Perm region in the global market. Methodology. The General methodological basis of the study was the dialectical- materialistic method of cognition of legal reality, which allowed to study the tools of development of small and medium-sized businesses in the Perm region in their development, to consider the problems of tools for the integrated development of small and medium-sized businesses in the Perm region, taking into account the changed socio-economic conditions in inseparable unity with other related tools relevant to the needs of digitalization of society. Such universal scientific methods as analysis and synthesis of doctrinal and normative materials were used in the work. In addition, special legal methods were used: the method of legal modeling, which allows to design possible legal situations using digital tools for the development of small and medium- sized businesses in the Perm region; the method of systematic interpretation used in assessing the actual impact of regional norms on the tools of development of small and medium-sized businesses in the Perm region. Results. The article proposes a new tool for the development of SMEs as a regional electronic platform for the promotion of goods, works and services of SMEs in the Perm region. Attention is paid to the level of digital literacy of SMEs and consumers of their goods, works and services: the conclusion about the lack of digital competence. Conclusion. It is necessary to improve the regional regulatory platform taking into account economic trends: it is important to introduce digital competencies everywhere, including at the professional level in relation to SMEs in the Perm region, in order to increase the business activity of young people and other representatives of the working population. As for the actual introduction of new tools for the development of small and medium-sized businesses in the Perm region, we propose that the regional legislator develop a new electronic information platform at the expense of the regional budget to promote goods, works and services sold by SMEs in the Perm region. We believe that the measures proposed by us to enhance the economic activity of SMEs can be perceived by other regions
Applicability of point dipoles approximation to all-dielectric metamaterials
All-dielectric metamaterials consisting of high-dielectric inclusions in a
low-dielectric matrix are considered as a low-loss alternative to resonant
metal-based metamaterials. In this contribution we investigate the
applicability of the point electric and magnetic dipoles approximation to
dielectric meta-atoms on the example of a dielectric ring metamaterial. Despite
the large electrical size of high-dielectric meta-atoms, the dipole
approximation allows for accurate prediction of the metamaterials properties
for the rings with diameters up to ~0.8 of the lattice constant. The results
provide important guidelines for design and optimization of all-dielectric
metamaterials.Comment: 10 pages, 5 fugures, submitted to Physical Review
The Power Flow Angle of Acoustic Waves in Thin Piezoelectric Plates
The curves of slowness and power flow angle (PFA) of quasi-antisymmetric (A0) and quasi-symmetric (S0) Lamb waves as well as quasi-shear-horizontal (SH0) acoustic waves in thin plates of lithium niobate and potassium niobate of X-,Y-, and Z-cuts for various propagation directions and the influence of electrical shorting of one plate surface on these curves and PFA have been theoretically investigated. It has been found that the group velocity of such waves does not coincide with the phase velocity for the most directions of propagation. It has been also shown that S0 and SH0 wave are characterized by record high values of PFA and its change due to electrical shorting of the plate surface in comparison with surface and bulk acoustic waves in the same material. The most interesting results have been verified by experiment. As a whole, the results obtained may be useful for development of various devices for signal processing, for example, electrically controlled acoustic switchers
The effect of electron surface scattering on fine metal particle electromagnetic radiation absorption
The magnetic dipole absorption cross section of a spherically shaped metal
particle was calculated in terms of kinetic approach. The particle considered
was placed in the field of a plane electromagnetic wave. The model of boundary
conditions was investigated taking into account the dependence of the
reflectivity coefficient both on the surface roughness parameter and on the
electron incidence angle. The results obtained were compared with theoretical
computation results for a model of combined diffusion-specular boundary
conditions of Fuchs.Comment: 9 pages, 5 figure
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