arXiv subjects

Alexander B. Balakin

Publications and source records attributed to Alexander B. Balakin.

At least 37 records · Page 2Linked to original sources

arXiv2021

Extended relativistic non-equilibrium thermostatics of stellar structures with radiation pressure

We establish the extended formalism for description of the static spherically symmetric relativistic non-equilibrium stellar systems in the formation of which the radiation pressure plays the key role. The main concept of this extended formalism inherits the ideas, on which the Israel-Stewart causal thermodynamics is based, but now the unit spacelike four-vector, indicated by the term director, is exploited in addition to the unit timelike medium velocity four-vector. An application of the extended formalism is considered; we analyze the profiles of the non-equilibrium pressure and temperature as the functions of guiding parameters introduced phenomenologically.

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arXiv2021

Nonlinear axion electrodynamics: Axionically induced electric flares in the early magnetized universe

We consider the nonlinearly extended Einstein-Maxwell-axion theory, which is based on the account for two symmetries: first, the discrete symmetry associated with the properties of the axion field, second, the Jackson's symmetry, prescribing to the electrodynamics to be invariant with respect to the rotation in the plane coordinated by the electric and magnetic fields. We derive the master equations of the nonlinearly extended theory, and apply them to the Bianchi-I model with magnetic field. The main result, describing the behavior of the nonlinearly coupled axion, electromagnetic and gravitational fields is the anomalous growth of the axionically induced electric field in the early magnetized Universe. The character of behavior of this anomalous electric field can be indicated by the term flare. We expect, that these electric flares can produce the electron-positron pair creation, significant acceleration of the born charged particles, and emission of the electromagnetic waves by these accelerated particles.

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arXiv2021

Towards nonlinear axion-dilaton electrodynamics: How can axionic dark matter mimic dilaton-photon interactions?

In the framework of the Einstein-Maxwell-axion-aether theory we establish the model, the Lagrangian of which contains the sin-type generalization of the term describing the axion-photon coupling, and the axionically induced cosine-type modification of the term attributed to the dilaton-photon interactions. The extension of the axion-dilaton-aether electrodynamics is inspired by the Jackson's idea concerning the internal symmetry of the equations of electromagnetism. The application of the extended theory to the anisotropic homogeneous cosmological model of the Bianchi-I type is considered. The exact solutions to the model evolutionary equations are obtained for the case, when the axionic dark matter is in the state of equilibrium, which is characterized by vanishing potential of the pseudoscalar field and its first derivative. The state of the axion-photon system, which is of a new type and is indicated as a dynamic equilibrium, is studied in the framework of electrodynamics with axionic non-linearity. We show that the nonlinear axion-photon interactions can mimic the dilaton-photon coupling. We discuss the stability of the model with respect to homogeneous fluctuations of the axion field.

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arXiv2021

Interaction of the axionic dark matter, dynamic aether, spinor and gravity fields as an origin of oscillations of the fermion effective mass

In the framework of the Einstein-Dirac-axion-aether theory we consider the quartet of self-interacting cosmic fields, which includes the dynamic aether, presented by the unit timelike vector field, the axionic dark mater, described by the pseudoscalar field, the spinor field associated with fermion particles, and the gravity field. The key, associated with the mechanism of self-interaction, is installed into the modified periodic potential of the pseudoscalar (axion) field constructed on the base of a guiding function, which depends on one invariant, one pseudo-invariant and two cross-invariants containing the spinor and vector fields. The total system of the field equations related to the isotropic homogeneous cosmological model is solved; we have found the exact solutions for the guiding function for three cases: nonzero, vanishing and critical values of the cosmological constant. Based on these solutions, we obtained the expressions for the effective mass of spinor particles, interacting with the axionic dark matter and dynamic aether. This effective mass is shown to bear imprints of the cosmological epoch and of the state of the cosmic dark fluid in that epoch.

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arXiv2020

Is the axionic dark matter an equilibrium system?

We consider an axionic dark matter model with a modified periodic potential for the pseudoscalar field in the framework of the axionic extension of the Einstein-aether theory. The modified potential is assumed to be equipped by the guiding function, which depends on the expansion scalar constructed as the trace of the covariant derivative of the aether velocity four-vector. The equilibrium state of the axion field is defined as the state, for which the modified potential itself and its first derivative with respect to the pseudoscalar field are equal to zero. We apply the developed formalism to the homogeneous isotropic cosmological model, and find the basic function, which describes the equilibrium state of the axionic dark matter in the expanding Universe.

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arXiv2020

Nonminimal dyons with regular gravitational, electric and axion fields

We consider the distribution of the axionic dark matter and the profiles of the axionically induced electric field on the background of a regular magnetic monopole. The background static spherically symmetric spacetime is considered to be regular at the center of the object and has no event horizons, the nonminimal interaction of strong gravitational and monopole type magnetic fields being the source, which provides this regularity. We assume that the pseudoscalar (axion) field also is nonminimally coupled to the electromagnetic and gravitational fields, and we search for solutions to the extended equations of nonminimal axion electrostatics, which satisfy two requirements: first, the axionically induced radial electric field vanishes at the center; second, the pseudoscalar field is regular at the center of the formed axionic dyon. We have found the set of parameters, describing the nonminimal axion-photon coupling, for which both requirements are satisfied. Properties of the two-parameter family of regular solutions to the equations of nonminimal axion electrostatics are analyzed numerically. The regular axionically induced electric field is shown to have the structure, which is typical for a simple electric layer.

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arXiv2020

Spontaneous color polarization as a modus originis of the dynamic aether

We suggest the phenomenological model of emergence of the dynamic aether as a result of decay of the SU(N) symmetric field configuration containing the multiplet of vector fields. The scenario of the transition to the dynamic aether, which is characterized by one unit timelike vector field associated with the aether velocity, is based on the idea of spontaneous color polarization analogous to the spontaneous electric polarization in ferroelectric materials. The mechanism of spontaneous color polarization is described in the framework of anisotropic cosmological model of the Bianchi-I type; it involves into consideration the idea of critical behavior of the eigenvalues of the tensor of color polarization in the course of the Universe accelerated expansion. The interim stage of transition from the color aether to the canonic dynamic aether takes the finite period of time, the duration of which is predetermined by the phenomenologically introduced critical value of the expansion scalar.

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arXiv2020

Fingerprints of the cosmological constant: Folds in the profiles of the axionic dark matter distribution in a dyon exterior

We consider the magnetic monopole in the axionic dark matter environment (axionic dyon) in the framework of the Reissner - Nordström - de Sitter model. Our aim is to study the distribution of the pseudoscalar (axion) and electric fields near the so-called folds, which are characterized by the profiles with the central minimum, the barrier on the left, and the maximum on the right of this minimum. The electric field in the fold-like zones is shown to change the sign twice, i.e., the electric structure of the near zone of the axionic dyon contains the domain similar to a double electric layer. We have shown that the described fold-like structures in the profile of the gravitational potential, and in the profiles of the electric and axion fields can exist, when the value of the dyon mass belongs to the interval enclosed between two critical masses, which depend on the cosmological constant.

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arXiv2020

New application of the Killing vector field formalism: Modified periodic potential and two-level profiles of the axionic dark matter distribution

We consider the structure of halos of the axionic dark matter, which surround massive relativistic objects with static spherically symmetric gravitational field and monopole-type magneto-electric fields. We work with the model of pseudoscalar field with the extended periodic potential, which depends on additional arguments proportional to the moduli of the Killing vectors; in our approach they play the roles of model guiding functions. The covariant model of the axion field with this modified potential is equipped with the extended formalism of the Killing vector fields, which is established in analogy with the formalism of the Einstein-aether theory, based on the introduction of a unit timelike dynamic vector field. We study the equilibrium state of the axion field, for which the extended potential and its derivative vanish, and illustrate the established formalism by the analysis of two-level axionic dark matter profiles, for which the stage delimiters relate to the critical values of the modulus of the timelike Killing vector field.

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arXiv2020

Magneto-electro-statics of axionically active systems: Induced field restructuring in magnetic stars

In the framework of Einstein-Maxwell-axion theory we consider a static field configuration in the outer zone of a magnetic star. We assume that this field configuration is formed by the following interacting quartet: a spherically symmetric gravitational field of the Reissner-Nordström type, pseudoscalar field, associated with an axionic dark matter, strong intrinsic magnetic field, and axionically induced electric field. Based on the analysis of the solutions to the master equations of the model, we show that the structure of the formed field configuration reveals the following triple effect. First, if the strong magnetic field of the star has the dipole component, the axionic halo around the magnetic star with spherically symmetric gravitational field is no longer spheroidal, and the distortion is induced by the axion-photon coupling; second, due to the distortion of the axionic halo the magnetic field is no longer pure dipolar, and the induced quadruple, octupole, etc., components appear thus redistributing the magnetic energy between the components with more steep radial profiles than the dipolar one; third, the interaction of the axionic and magnetic fields produces the electric field, which inherits their multipole structure. We attract attention to possible applications of the predicted field restructuring to the theory of axionic rotating magnetars.

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arXiv2019

Dynamo-optically active media: New aspects of the Minkowski-Abraham controversy

Based on the covariant variation formalism, two versions of the symmetric effective stress-energy tensor of the electromagnetic field in a dynamo-optically active relativistic media are reconstructed in the framework of the tetrad and aether paradigms, respectively. We show that the energy density scalars and pressure tensors coincide for both versions of the stress-energy tensors, however, the corresponding energy flux four-vectors happen to be different in general case. This mathematical fact adds new arguments into the 100-year-long discussion, which is called Minkowski-Abraham controversy and is connected with the correct definition of the electromagnetic energy flux in a continuous media. We consider three examples: first, the axionically active vacuum; second, the spatially isotropic moving dielectric medium; third, the dynamo-optically active medium. We discuss possible applications of the elaborated formalism.

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arXiv2019

Axionic extension of the Einstein-aether theory: How does dynamic aether regulate the state of axionic dark matter?

In the framework of axionic extension of the Einstein-aether theory we establish the model, which describes a stiff regulation of the behavior of axionic dark matter by the dynamic aether. The aether realizes this procedure via the modified Higgs potential, designed for modeling of nonlinear self-interaction of pseudoscalar (axion) field; the modification of this potential is that its minima are not fixed, and their positions and depths depend now on the square of the covariant derivative of the aether velocity four-vector. Exact solutions to the master equations, modified correspondingly, are obtained in the framework of homogeneous isotropic cosmological model. The effective equation of state for axionic dark matter is of the stiff type. Homogeneous perturbations of the pseudoscalar (axion) field, of the Hubble function and of the scale factor are shown to fade out with cosmological time, there are no growing modes, the model of stiff regulation is stable.

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arXiv2019

Polarization and stratification of axionically active plasma in a dyon magnetosphere

The state of a static spherically symmetric relativistic axionically active multi-component plasma in the gravitational, magnetic and electric fields of an axionic dyon is studied in the framework of the Einstein - Maxwell - Boltzmann - axion theory. We assume that the equations of axion electrodynamics, the covariant relativistic kinetic equations, and the equation for the axion field with modified Higgs-type potential are nonlinearly coupled; the gravitational field in the dyon exterior is assumed to be fixed and to be of the Reissner-Nordström type. We introduce the extended Lorentz force, which acts on the particles in the axionically active plasma, and analyze the consequences of this generalization. The analysis of exact solutions, obtained in the framework of this model for the relativistic Boltzmann electron-ion and electron-positron plasmas, as well as, for degenerated zero-temperature electron gas, shows that the phenomena of polarization and stratification can appear in plasma, attracting attention to the axionic analog of the known Pannekoek-Rosseland effect.

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arXiv2018

Dark Energy and Dark Matter Interaction: Kernels of Volterra Type and Coincidence Problem

We study a new exactly solvable model of coupling of the Dark Energy and Dark Matter, in the framework of which the kernel of non-gravitational interaction is presented by the integral Volterra-type operator well-known in the classical theory of fading memory. Exact solutions of this isotropic homogeneous cosmological model were classified with respect to the sign of the discriminant of the cubic characteristic polynomial associated with the key equation of the model. Energy-density scalars of the Dark Energy and Dark Matter, the Hubble function and acceleration parameter are presented explicitly; the scale factor is found in quadratures. Asymptotic analysis of the exact solutions has shown that the Big Rip, Little Rip, Pseudo Rip regimes can be realized with the specific choice of guiding parameters of the model. We show that the Coincidence problem can be solved if we consider the memory effect associated with the interactions in the Dark Sector of the Universe.

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arXiv2018

The extended Einstein-Maxwell-aether-axion model: Exact solutions for axionically controlled pp-wave aether modes

The extended Einstein-Maxwell-aether-axion model describes internal interactions inside the system, which contains gravitational, electromagnetic fields, the dynamic unit vector field describing the velocity of an aether, and the pseudoscalar field associated with the axionic dark matter. The specific feature of this model is that the axion field controls the dynamics of the aether through the guiding functions incorporated into the Jacobson's constitutive tensor. Depending on the state of the axion field these guiding functions can control and switch on or switch off the influence of acceleration, shear, vorticity and expansion of the aether flow on the state of physical system as a whole. We obtain new exact solutions, which possess the pp-wave symmetry, and indicate them by the term pp-wave aether modes in contrast to the pure pp-waves, which can not propagate in this field conglomerate. These exact solutions describe a specific dynamic state of the pseudoscalar field, which corresponds to one of the minima of the axion potential, and switches off the influence of shear and expansion of the aether flow; the model does not impose restrictions on the Jacobson's coupling constants and on the axion mass. Properties of these new exact solutions are discussed.

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arXiv2018

SU(N) - symmetric dynamic aether: General formalism and a hypothesis on spontaneous color polarization

The SU(N)-symmetric generalization of the model of the electromagnetically active dynamic aether is formulated. This generalization is based on the introduction of a Yang-Mills gauge field instead of the Maxwell field, and of a SU(N)-multiplet of vector fields instead of the standard single vector field. In the framework of the second order version of the effective field theory this generalization includes three constitutive tensors, which are the SU(N) extensions of the tensors appeared in the Einstein-Maxwell-aether theory; we reconstructed the full-format set of these constitutive tensors. The total self-consistent system of master equations for the gauge, vector and gravitational fields is obtained by the variation procedure. The general model of the SU(N)-symmetric dynamic aether is reduced to the extended Einstein-Yang-Mills-aether model by the ansatz about spontaneous color polarization of the vector fields. In fact, this ansatz requires the vector fields, which form the SU(N) multiplet, to become parallel in the group (color) space due to a phase transition, and a new selected direction in the group space to appear, thus converting it into the anisotropic color space.

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arXiv2018

Non-minimal Einstein-Maxwell theory: the Fresnel equation and the Petrov classification of a trace-free susceptibility tensor

We construct a classification of dispersion relations for the electromagnetic waves non-minimally coupled to the space-time curvature, based on the analysis of the susceptibility tensor, which appears in the non-minimal Einstein-Maxwell theory. We classify solutions to the Fresnel equation for the model with a trace-free non-minimal susceptibility tensor according to the Petrov scheme. For all Petrov types we discuss specific features of the dispersion relations and plot the corresponding wave surfaces.

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arXiv2017

Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether

In the framework of the Einstein-Maxwell-aether theory we study the birefringence effect, which can occur in the pp-wave symmetric dynamic aether. The dynamic aether is considered to be latently birefringent quasi-medium, which displays this hidden property if and only if the aether motion is non-uniform, i.e., when the aether flow is characterized by the non-vanishing expansion, shear, vorticity or acceleration. In accordance with the dynamo-optical scheme of description of the interaction between electromagnetic waves and the dynamic aether, we shall model the susceptibility tensors by the terms linear in the covariant derivative of the aether velocity four-vector. When the pp-wave modes appear in the dynamic aether, we deal with a gravitationally induced degeneracy removal with respect to hidden susceptibility parameters. As a consequence, the phase velocities of electromagnetic waves possessing orthogonal polarizations do not coincide, thus displaying the birefringence effect. Two electromagnetic field configurations are studied in detail: longitudinal and transversal with respect to the aether pp-wave front. For both cases the solutions are found, which reveal anomalies in the electromagnetic response on the action of the pp-wave aether mode.

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