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V. M. Red'kov

Publications and source records attributed to V. M. Red'kov.

At least 37 records · Page 2Linked to original sources

Transitivity in polarization optics and the diagonalization of quadratic forms

Any one measurement with polarized light makes it possible to fix the Mueller matrices of the Lorentz type with up to four arbitrary numeric parameters (x, u; z, w). These parameters are subject to the quadratic condition. It is demonstrated that the quadratic form can be diagonalized; in the case of partially polarized light four diagonal coefficients turn out to benon-zero and positive; in the case of completely polarized light two diagonal coefficients equal to zero.

physics.optics↗

On exact solutions for quantum particles with spin S= 0, 1/2, 1 and de Sitter event horizon

Exact wave solutions for particles with spin 0, 1/2 and 1 in the static coordinates of the de Sitter space-time model are examined in detail. Firstly, for a scalar particle, two pairs of linearly independent solutions are specified explicitly: running and standing waves. A known algorithm for calculation of the reflection coefficient $R_{εj}$ on the background of the de Sitter space-time model is analyzed. It is shown that the determination of R_{εj} requires an additional constrain on quantum numbers ερ/ \hbar c >> j, where ρis a curvature radius. When taken into account of this condition, the R_{εj} vanishes identically. It is claimed that the calculation of the reflection coefficient R_{εj} is not required at all because there is no barrier in an effective potential curve on the background of the de Sitter space-time. The same conclusion holds for arbitrary particles with higher spins, it is demonstrated explicitly with the help of exact solutions for electromagnetic and Dirac fields.

hep-th↗

Coulomb problem for a Dirac particle in flat Minkowski space and the Heun functions, extension to curved models

It is shown that there exist several ways to treat the quantum-mechanical Coulomb problem for a Dirac particle in flat Minkowski space with the help of the Heun differential equation, Fuchs's equation with four singular points. When extending the problem to curved spaces of constant curvature, Lobachevsky H_{3} and Rimann S_{3}, there arise 2-nd order differential equations of the Fuchs type with 6 singular points, a method to get relevant equations with five singular points has been elaborated.

math-ph↗

Rarita--Schwinger for spin 3/2 field and separation of the variables in static coordinates of de Sitter space, Schrödinger tetrad basis

Rarita-Schwinger approach to description of a massive spin 3/2 particle is investigated in static coordinates of the de Sitter space-time. The general covariant system, derived from the relevant Lagrangian, is presented as a main wave equation and additional constraints in the form of first order deferential and algebraic relations. With the use of an extended Schrödinger tetrad basis and technique of Wigner D-functions the separation of the variable performed. 16 radial equations reduce to 8 ones through diagonalization of $P$-inversion operator for spin 3/2 field.

math-ph↗

Particle with spin S=3/2 in Riemannian space-time

Equations for 16-component vector-bispinor field, originated from Rarita-Schwinger Lagrangian for spin 3/2 field extended to Riemannian space-time are investigated. Additional general covariant constrains for the field are produced, which for some space-time models greatly simplify original wave equation. Peculiarities in description of the massless spin 3/2 field are specified. In the flat Minkowski space for massless case there exist gauge invariance of the main wave equation, which reduces to possibility to produce a whole class of trivial solutions in the the form of 4-gradient of arbitrary (gauge) bispinor function, Ψ^{0}_{c} = \partial_{c} ψ. Generalization of that property for Riemannian model is performed; it is shown that in general covariant case solutions of the gradient type Ψ^{0}_β = (\nabla_β + Γ_β)Ψexist in space-time regions where the Ricci tensor obeys an identity R_{αβ} - {1 \over 2} R g_{αβ} = 0.

math-ph↗

Particle with spin 1 in a magnetic field on the spherical plane S_{2}

There are constructed exact solutions of the quantum-mechanical equation for a spin S=1 particle in 2-dimensional Riemannian space of constant positive curvature, spherical plane, in presence of an external magnetic field, analogue of the homogeneous magnetic field in the Minkowski space. A generalized formula for energy levels describing quantization of the motion of the vector particle in magnetic field on the 2-dimensional space S_{2} has been found, nonrelativistic and relativistic equations have been solved.

math-ph↗

Spherical waves for Dirac--Kähler and Dirac particles, formal relations between boson and fermion solutions

Tetrad based equation for Dirac-Kähler particle is solved in spherical coordinates in the flat Minkocski space-time. Spherical solutions of boson type (J =0,1,2,...) are constructed. After performing a special transformation over spherical boson solutions of the Dirac-Kähler equation, 4 \times 4-matrices U(x) \Longrightarrow V(x), simple linear expansions of the four rows of new representativeof the Dirac--Kähler field V(x) in terms of spherical fermion solutions Ψ_{i}(x) of the four ordinary Dirac equations have been derived. However, this fact cannot be interpreted as the possibility not to distinguish between the Dirac-Kähler field and the system four Dirac fermions. The main formal argument is that the special transformation (I \otimes S(x)) involved does not belong to the group of tetrad local gauge transformation for Dirac-Kähler field, 2-rank bispinor under the Lorentz group. Therefore, the linear expansions between boson and fermion functions are not gauge invariant under the group of local tetrad rotations.

math-ph↗

Spin 1/2 particle in the field of the Dirac string on the background of de Sitter space-time

The Dirac monopole string is specified for de Sitter cosmological model. Dirac equation for spin 1/2 particle in presence of this monopole has been examined on the background of de Sitter space-time in static coordinates. Instead of spinor monopole harmonics, the technique of Wigner D-functions is used. After separation of the variables, detailed analysis of the radial equations is performed; four types of solutions, singular, regular, in- and out- running waves, are constructed in terms of hypergeometric functions. The complete set of spinor wave solutions Ψ_{ε, j,m, λ}(t,r, θ, ϕ) has been constructed, special attention is given to treating the states of minimal values of the total angular moment j_{\min}.

quant-ph↗

Lorentz group theory and polarization of the light

Some facts of the theory of the Lorentz group are specified for looking at the problems of light polarization optics in the frames of vector Stokes-Mueller and spinor Jones formalism. In view of great differences between properties of isotropic and time-like vectors in Special Relativity we should expect principal differences in describing completely polarized and partly polarized light. In particular, substantial differences are revealed when turning to spinor techniques in the context of the polarized light. Because Jones complex formalism has close relation to spinor objects of the Lorentz group, within the field of the light polarization we could have physical realizations on the optical desk of some subtle topological distinctions between orthogonal L_{+}^{\uparrow} =SO_{0}(3.1) and spinor SL(2.C) groups. These topological differences of the groups find their corollaries in the problem of the so-called spinor structure of physical space-time, some new points are considered.

math-ph↗

Dirac-Kahler equation in curved space-time, relation between spinor and tensor formulations

A common view is that generalization of a wave equation on Riemannian space-time is substantially determined by what a particle is - boson or fermion. As a rule, they say that tensor equations for bosons are extended in a simpler way then spinor equations for fermions. In that context, a very interesting problem is of extension a wave equation for Dirac--Kähler field (Ivanenko--Landau field was historically first term, also the term a vector field of general type was used). The article relates a generally covariant tensor formalism to a spinor one when these both are applied to description of the Dirac-Kähler field in a Rimannian space-time. Both methods are taken to be equivalent and the tensor equations are derived from spinor ones. It is shown that, for characterization of Dirac-Kähler's tensor components, two alternative approaches are suitable: these are whether a tetrad-based pseudo tensor classification or a generally coordinate pseudo tensor one. By imposing definite restrictions on the the Dirac-Kähler function, we have produced the general covariant form of wave equations for scalar, pseudoscalar, vector, and pseudovector particles.

math-ph↗

Spinor Structure of P-Oriented Space, Kustaanheimo-Stifel and Hopf Bundle - Connection between Formalisms

In the work some relations between three techniques, Hopf's bundle, Kustaanheimo-Stiefel's bundle, 3-space with spinor structure have been examined. The spinor space is viewed as a real space that is minimally (twice as much) extended in comparison with an ordinary vector 3-space: at this instead of 2π-rotation now only 4π-rotation is taken to be the identity transformation in the geometrical space. With respect to a given P-orientation of an initial unextended manyfold, vector or pseudovector one, there may be constructed two different spatial spinors, $ξ$ and $η$, respectively. By definition, those spinors provide us with points of the extended space odels, each spinor is in the correspondence $2 \longrightarrow 1 with points of a vector space. For both models an explicit parametrization of the spinors ξand ηby spherical and parabolic coordinates is given, the parabolic system turns out to be the most convenient for simple defining spacial spinors. Fours of real-valued coordinates by Kustaanheimo-Stiefel, U_{a} and V_{a}, real and imaginary parts of complex spinors ξand ηrespectively, obey two quadratic constraints. So that in both cases, there exists a Hopf's mapping from the part of 3-sphere S_{3} into the entire 2-sphere S_{2}. Relation between two spacial spinor is found: η= (ξ- iσ^{2}ξ^{*})/\sqrt{2}, in terms of Kustaanheimo-Stiefel variables U_{a} and V_{a} it is a linear transformation from SO(4.R), which does not enter its sub-group generated by SU(2)-rotation over spinors.

math-ph↗

Particle with spin 2 and anomalous magnetic moment in external electromagnetic and gravitational fields

Tensor 50-component form of the first order relativistic wave equation for a particle with spin 2 and anomalous magnetic moment is extended to the case of an arbitrary curved space-time geometry. An additional parameter considered in the presence of only electromagnetic field as related to anomalous magnetic moment, turns to determine additional interaction terms with external geometrical background through Ricci R_{kl} and Riemann R_{klmn} tensors.

math-ph↗

Quaternions and Small Lorentz Groups in Noncommutative Electrodynamics

Non-linear electrodynamics arising in the frames of field theories in noncommutative space-time is examined on the base of quaternion formalism. The problem of form-invariance of the corresponding nonlinear constitutive relations governed by six noncommutativity parameters $θ_{kl}$ or quaternion \underline{K} = \underlineθ - i \underlineε is explored in detail. Two Abelian 2-parametric small groups, SO(2) \otimes O(1.1) or T_{2}, depending on invariant length \underline{K}^{2}\neq 0 or \underline{K}^{2}= 0 respectively, have been found. The way to interpret both small groups in physical terms consists in factorizing corresponding Lorentz transformations into Euclidean rotations and Lorentzian boosts. In the context of general study of various dual symmetries in noncommutative field theory, it is demonstrated explicitly that the nonlinear constitutive equations under consideration are not invariant under continuous dual rotations, instead only invariance under discrete dual transformation exists.

math-ph↗

Graviton in a Curved Space-Time Background and Gauge Symmetry

Pauli-Fierz approach to description of a massless spin-2 particle is investigated in the framework of 30-component first order relativistic wave equation theory on a curved space-time background. It is shown that additional gauge symmetry of massless equations established by Pauli-Fierz can be extended only to curved space-time regions where Ricci tensor vanishes. In all such space-time models the generally covariant S=2 massless wave equation exhibits gauge symmetry property, otherwise it is not so.

math-ph↗

Geometry of 3-Spaces with Spinor Structure

A special approach to examine spinor structure of 3-space is proposed. It is based on the use of the concept of a spatial spinor defined through taking the square root of a real-valued 3-vector. Two sorts of spatial spinor according to P-orientation of an initial 3-space are introduced: properly vector or pseudo vector one. These spinors, ηand ξ, turned out to be different functions of Cartesian coordinates. To have a spinor space model, you ought to use a doubling vector space. The main idea is to develop some mathematical technique to work with such extended models. Two sorts of spatial spinors are examined with the use of curvilinear coordinates (y_{1},y_{2},y_{3}): cylindrical parabolic, spherical and parabolic ones. Transition from vector to spinor models is achieved by doubling initial parameterizing domain G(y_{1},y_{2},y_{3}) \Longrightarrow \tilde{G}(y_{1},y_{2},y_{3}) with new identification rules on the boundaries. Different spinor space models are built on explicitly different spinor fields ξ(y) and η(y). Explicit form of the mapping spinor field η(y) of pseudo vector model into spinor ξ(y) of properly vector one is given, it contains explicitly complex conjugation.

math-ph↗

Ricci Coefficients in Covariant Dirac Equation, Symmetry Aspects and Newman-Penrose Approach

The paper investigates how the Ricci rotation coefficients act in the Dirac equation in presence of external gravitational fields described in terms of Riemannian space-time geometry. It is shown that only 8 different combinations of the Ricci coefficients γ_{abc}(x) are involved in the Dirac equation. They are combined in two 4-vectors B_{a}(x) and C_{a}(x) under local Lorentz group which has status of the gauge symmetry group. In all orthogonal coordinates one of these vectors, "pseudovector" C_{a}(x), vanishes identically. The gauge transformation laws of the two vectors are found explicitly. Connection of these B_{a}(x) and A_{a}(x) with the known Newman-Penrose coefficients is established. General study of gauge symmetry aspects in Newman-Penrose formalism is performed. Decomposition of the Ricci object, "tensor" γ_{abc}(x), into two "spinors" γ(x) and \barγ(x) is done. At this Ricci rotation coefficients are divided into two groups:12 complex functions γ(x) and 12 conjugated to them \barγ(x). Components of spinor \barγ(x) coincide with 12 spin coefficients by Newman-Penrose. The formulas for gauge transformations of spin coefficients under local Lorentz group are derived. There are given two solutions to the gauge problem: one in the compact form of transformation laws for spinors γ(x) and \barγ(x), and another as detailed elaboration of the latter in terms of 12 spin coefficients.

math-ph↗

Exact solutions for a quantum-mechanical particle with spin 1 and additional intrinsic characteristics in a homogeneous magnetic field

With the use of the general covariant matrix 10-dimensional Petiau-Duffin-Kemmer formalism in cylindrical coordinates exact solutions of the quantum-mechanical equation for a particle with spin 1 in the presence of an external homogeneous magnetic field are constructed. Three linearly independent types of solutions are separated; in each case the formula for the energy levels has been found.Within similar technique for the quantum-mechanical equation for a particle with spin 1 and additional intrinsic electromagnetic characteristics - polarizability, exact solutions are found in the presence of an external homogeneous magnetic field.

quant-ph↗

Spherical waves of spin 1 particle in anti de Sitter space-time

Three possible techniques to deal with a vector particle in the anti de Sitter cosmological model are viewed: Duffin-Kemmer-Petiau matrix formalism based on the general tetrad recipe, group theory 5-dimensional approach based on the symmetry group SO(3.2), anda tetrad form of Maxwell equations in complex Riemann-Silberstein-Majorana-Oppenheimer representation. In the first part, a spin 1 massive field is considered in static coordinates of the anti de Sitter space-time in tetrad-based approach. The complete set of spherical wave solutions with quantum numbers (ε, j,m,l) is constructed; angular dependence in wave functions is described with the help of Wigner functions. The energy quantization rule has been found. Transition to massless case of electromagnetic field is specified, and electromagnetic solutions in Lorentz gauge have been constructed. In the second part, the problem of a particle with spin 1 is considered on the base of 5-dimensional wave equation specified in the same static coordinates. In the third part, a rarely used approach, based on tetrad form of Maxwell equations in complex representation is examined in the anti de Sitter model.

math-ph↗