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Reshetnyak A.A.,RAS Institute of Strength Physics and Materials Science
Physics of Particles and Nuclei Letters | Year: 2017

Lagrangian descriptions of irreducible and reducible integer higher-spin representations of the Poincare group subject to a Young tableaux Y [ŝ1, ŝ2] with two columns are constructed within a metric-like formulation in a d-dimensional flat space-time on the basis of a BRST approach extending the results of [arXiv:1412.0200[hep-th]]. A Lorentz-invariant resolution of the BRST complex within both the constrained and unconstrained BRST formulations produces a gauge-invariant Lagrangian entirely in terms of the initial tensor field Φ[µ]ŝ1,[µ]ŝ2 subject to Y [ŝ1, ŝ2] with an additional tower of gauge parameters realizing the (ŝ1 −1)-th stage of reducibility with a specific dependence on the value (ŝ1−ŝ2) = 0, 1,…, ŝ1. Minimal BRST-BV action is suggested, being proper solution to the master equation in the minimal sector and providing objects appropriate to construct interacting Lagrangian formulations with mixed-antisymmetric fields in a general framework. © 2017, Maik Nauka Publishing / Springer SBM. All rights reserved.


Burdik C.,Czech Technical University | Reshetnyak A.,RAS Institute of Strength Physics and Materials Science
Journal of Physics: Conference Series | Year: 2012

We derive non-linear commutator HS symmetry algebra, which encode unitary irreducible representations of AdS group subject to Young tableaux Y(s 1,..., s k) with κ ≥ 2 rows on d-dimensional anti-de-Sitter space. Auxiliary representations for specially deformed non-linear HS symmetry algebra in terms of generalized Verma module in order to additively convert a subsystem of second-class constraints in the HS symmetry algebra into one with first-class constraints are found explicitly for the case of HS fields for κ = 2 Young tableaux. The oscillator realization over Heisenberg algebra for obtained Verma module is constructed. The results generalize the method of auxiliary representations construction for symplectic sp(2κ) algebra used for mixed-symmetry HS fields on a flat spaces and can be extended on a case of arbitrary HS fields in AdS-space. Gauge-invariant unconstrained reducible Lagrangian formulation for free bosonic HS fields with generalized spin (s 1, s 2) is derived.


Buchbinder I.L.,Federal University of Juiz de fora | Buchbinder I.L.,Tomsk State Pedagogical University | Reshetnyak A.,RAS Institute of Strength Physics and Materials Science
Nuclear Physics B | Year: 2012

We construct a Lagrangian description of irreducible integer higher spin representations of the Poincaré-group with an arbitrary Young tableaux having k rows, on a basis of the universal BRST approach. Starting with a description of bosonic mixed-symmetry higher spin fields in a flat space of any dimension in terms of an auxiliary Fock space associated with special Poincaré module, we realize a conversion of the initial operator constraint system (constructed with respect to the relations extracting irreducible Poincaré-group representations) into a first-class constraint system. For this purpose, we find, for the first time, auxiliary representations of the constraint subalgebra, to be isomorphic due to Howe duality to sp(2k) algebra, and containing the subsystem of second-class constraints in terms of new oscillator variables. We propose a universal procedure of constructing unconstrained gauge-invariant Lagrangians with reducible gauge symmetries describing the dynamics of both massless and massive bosonic fields of any spin. It is shown that the space of BRST cohomologies with a vanishing ghost number is determined only by the constraints corresponding to an irreducible Poincaré-group representation. As examples of the general procedure, we formulate the method of Lagrangian construction for bosonic fields subject to arbitrary Young tableaux having 3 rows and derive the gauge-invariant Lagrangian for new model of massless rank-4 tensor field with spin (2,1,1) and second stage reducible gauge symmetries. © 2012 Elsevier B.V.


Dmitriev A.I.,RAS Institute of Strength Physics and Materials Science | Osterle W.,BAM Federal Institute of Materials Research and Testing
Tribology International | Year: 2010

The frictional behavior at local contacts in an automotive brake system was analysed on the basis of computer simulation by movable cellular automata method. The boundary conditions of the model were adjusted to experimental observations obtained by TEM. The model proved to be adequate for simulating mechanical mixing and velocity accommodation at the pad-disc interface. Dynamics of particle interaction were visualized by showing rotation angles and velocity vectors. The model provided information on the development of plastic deformation for metal-on-metal contacts and on crack formation at graphite lamellae of cast iron disc. Results are in agreement with conventional friction theories. © 2009 Elsevier Ltd. All rights reserved.


Osterle W.,BAM Federal Institute of Materials Research and Testing | Dmitriev A.I.,RAS Institute of Strength Physics and Materials Science
Wear | Year: 2011

Automotive braking is based on dry friction between fixed pads and a rotating disc. Besides macroscopic thermo-physical properties, the development of topographic features on the mesoscopic scale and the nanostructure of the third body formed by wear processes, determine brake performance properties. Whereas modelling on the atomistic scale is suitable to understand mechanisms leading to nanocrystalline surface films, the properties of such films can be assessed best with a model based on movable cellular automata (MCA). It turned out that the presence of at least 10% of soft nanoinclusions is most essential in respect to smooth sliding conditions. It made no major difference whether graphite or copper particles were assumed as soft nanoinclusions. The third body material is not only the stuff which spreads over contact areas, but it also contributes to contact size by wear particle compaction and formation of secondary contact areas. The evolution of contact size is the major feature of mesoscopic modelling and thus it is capable to model and explain dynamic changes of the coefficient of friction (COF) during certain brake operations. Although it is still ambiguous in many cases which feature has the major impact on friction behaviour, the following conclusions can be drawn. The reinforcing ingredients of the pad material serve as primary contact sites and thus define the starting condition for mesoscopic simulations. A certain amount of wear is necessary to provide a third body which is capable to form secondary contact sites and friction layers screening the first body materials. The composition and nanostructure of the third body is important as well, because it determines the friction level and is responsible for smooth sliding conditions. © 2011 Elsevier B.V.


Reshetnyak A.A.,RAS Institute of Strength Physics and Materials Science
Physics of Particles and Nuclei | Year: 2010

The spectrum of superstring theory on the AdS5 × S5 Ramond-Ramond background in tensionless limit contains integer and half-integer higher-spin fields subject at most to two-rows Young tableaux Y(s1, s2). We review the details of a gauge-invariant Lagrangian description of such massive and massless higher-spin fields in anti-de-Sitter spaces with arbitrary dimensions. The procedure is based on the construction of Verma modules, its oscillator realizations and of a BFV-BRST operator for non-linear algebras encoding unitary irreducible representations of AdS group. © 2010 Pleiades Publishing, Ltd.


Makarov P.V.,RAS Institute of Strength Physics and Materials Science
Physical Mesomechanics | Year: 2010

The paper considers common nonlinear characteristics of inelastic deformation and fracture of loaded solids and similarity of numerical solutions of a nonlinear system of relevant partial differential equations. The self-similarity of inelastic strain and damage accumulation in the entire hierarchy of scales-from interatomic distances up to tectonic faults of many thousands of kilometers in the Earth crust-ensures qualitative similarity of fracture scenarios whatever the scale of deformation and rheology of a medium. The common properties of deformed systems are spatial localization of inelastic strain and damage accumulation in the entire hierarchy of scales, further temporal strain localization as a superfast autocatalytic blow-up process, slow dynamics (deformation fronts or slow motions), and strain activity migration due to long-range space-time correlations over the entire hierarchy of scales. Thus, fracture evolves as a sequence of catastrophes of increasing scales up to macroscales. It is shown that self-organized criticality of any deformed system does not exclude the possibility to predict the time and the place of a future catastrophic event. Precursors of similar large-scale events can be (i) frozen strain activity in the immediate vicinity of a formed main crack or fault and (ii) generation of trains of deformation fronts (damage fronts) in this region and their flow toward the site of a formed main crack (fault). © 2010.


Panin V.E.,RAS Institute of Strength Physics and Materials Science | Egorushkin V.E.,RAS Institute of Strength Physics and Materials Science
Physical Mesomechanics | Year: 2013

A nonlinear wave approach to the description of a deformable solid as a multiscale hierarchically organized system was developed. It is shown that all types of strain-induced defects can be represented as curvature solitons of crystal structure-generalized structural wave carriers of plastic deformation and fracture of solids. The scale of a curvature soliton defines the type of a strain-induced defect. The waves of curvature solitons can be dispersed. A curvature soliton generates a crack if the Gibbs thermodynamic potential in a local curvature zone is positive and the material undergoes structural phase decay. © 2013 Pleiades Publishing, Ltd.


Chertova N.V.,RAS Institute of Strength Physics and Materials Science
Physical Mesomechanics | Year: 2013

The mechanisms of plane harmonic wave propagation in homogeneous and interfaced elastic-viscoplastic media are considered using the field theory of defects with kinematic identities of a dislocation-containing elastic continuum and dynamic equations of the gauge theory of dislocations. The reflection and refraction coefficients were determined for displacement waves and defect field waves with the defect field characterized by the dislocation density tensor and flux density tensor. The dependence of the coefficients on the parameters of the interfaced media is analyzed. © 2013 Pleiades Publishing, Ltd.


Ivanov K.V.,RAS Institute of Strength Physics and Materials Science | Naydenkin E.V.,RAS Institute of Strength Physics and Materials Science
Scripta Materialia | Year: 2012

Deformation mechanisms occurring by plastic flow of ultrafine grained aluminum processed by equal channel angular pressing at room temperature have been investigated using deformation relief on the pre-polished surface of the sample tested. The deformation behavior and the offsetting of marker lines suggest the development of grain boundary sliding in addition to intragrain dislocation slip. The contribution of grain boundary sliding to the overall deformation calculated using displacement of grains relative to each other was found to reach 24%. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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