arXiv subjects

Yu. A. Sitenko

Publications and source records attributed to Yu. A. Sitenko.

At least 19 recordsLinked to original sources

arXiv2022

Induced vacuum energy density of quantum charged scalar matter in the background of an impenetrable magnetic tube with the Neumann boundary condition

We consider vacuum polarization of charged scalar matter field outside the tube with magnetic flux inside. The tube is impenetrable for quantum matter and the perfectly rigid (Neumann) boundary condition is imposed at its surface. We write expressions for induced vacuum energy density for the case of a space of arbitrary dimension and for an arbitrary value of the magnetic flux. We do the numerical computation for the case of half-integer flux value in the London flux units and (2+1)-dimensional space-time. We show that the induced vacuum energy of the charged scalar matter field is induced if the Compton wavelength of the matter field exceeds the transverse size of the tube considerably. We show that vacuum energy is periodic in the value of the magnetic flux of the tube, providing a quantum-field-theoretical manifestation of the Aharonov-Bohm effect. The dependencies of the induced vacuum energy upon the distance from the center of the tube under the different values of its thickness were obtained. Obtained results are compared to the results obtained earlier in the case of the perfectly reflecting (Dirichlet) boundary condition. It is shown that the value of the induced vacuum energy density in the case of the Neumann boundary condition is greater than in the case of the Dirichlet boundary condition.

hep-th↗

arXiv2022

Induced vacuum current and magnetic flux in quantum scalar matter in the background of a vortex defect with the Neumann boundary condition

A topological defect in the form of the Abrikosov-Nielsen-Olesen vortex in a space of arbitrary dimension is considered as a gauge-flux-carrying tube that is impenetrable for quantum matter. Charged scalar matter field is quantized in the vortex background with the perfectly rigid (Neumann) boundary condition imposed at the side surface of the vortex. We show that a current circulating around the vortex is induced in the vacuum, if the Compton wavelength of the matter field exceeds the transverse size of the vortex considerably. The vacuum current is periodic in the value of the gauge flux of the vortex, providing a quantum-field-theoretical manifestation of the Aharonov-Bohm effect. The vacuum current leads to the appearance of an induced vacuum magnetic flux that for some values of the tube thickness exceeds the vacuum magnetic flux induced by a singular vortex filament. The results were compared to the results obtained earlier in the case of the perfectly reflecting (Dirichlet) boundary condition imposed at the side surface of the vortex. It is shown that the absolute value of the induced vacuum current and the induced vacuum magnetic flux in the case of the Neumann boundary condition is greater than in the case of the Dirichlet boundary condition.

hep-th↗

arXiv2018

Chiral effects in magnetized quantum spinor matter in particle and astroparticle physics

Quantum spinor matter in extremal conditions (high densities and temperatures, presence of strong magnetic fields) have drawn the attention of researchers in diverse areas of contemporary physics, ranging from cosmology, high-energy and astroparticle physics to condensed matter physics. We study an impact of the confining boundary conditions on the properties of physical systems with hot dense magnetized ultrarelativistic spinor matter and elucidate a significant role of boundaries for such systems.

hep-th↗

arXiv2016

Hot dense magnetized spinor matter in particle and astroparticle physics: the role of boundaries

We study the influence of boundaries on chiral effects in hot dense relativistic spinor matter in a strong magnetic field which is orthogonal to the boundaries. The most general set of boundary conditions ensuring the confinement of matter within the boundaries is employed. We find that the chiral magnetic effect disappears, whereas the chiral separation effect stays on, becoming dependent on temperature and on a choice of boundary conditions. As temperature increases from zero to large values, a stepped-shape behaviour of the chiral separation effect as a function of chemical potential is changed to a smooth one. A choice of the boundary condition can facilitate either amplification or diminution of the chiral separation effect; in particular, the effect can persist even at zero chemical potential, if temperature is finite. This points at a significant role of boundaries for physical systems with hot dense magnetized spinor matter, i.e. compact astrophysical objects (neutron stars and magnetars), relativistic heavy-ion collisions, novel materials known as the Dirac and Weyl semimetals.

hep-th↗

arXiv2016

Hot dense magnetized ultrarelativistic spinor matter in a slab

Properties of hot dense ultrarelativistic spinor matter in a slab of finite width, placed in a transverse uniform magnetic field, are studied. The admissible set of boundary conditions is determined by the requirement that spinor matter be confined inside the slab. In thermal equilibrium, the chiral separation effect in the slab is shown to depend on both temperature and chemical potential; this is distinct from the unrealistic case of the magnetic field filling the unbounded (infinite) medium, when the effect is temperature independent. In the realistic case of the slab, a stepwise behaviour of the axial current density at zero temperature is smoothed out as temperature increases, turning into a linear behaviour at infinitely large temperature. A choice of boundary conditions can facilitate either augmentation or attenuation of the chiral separation effect; in particular, the effect can persist even at zero chemical potential, if temperature is finite. Thus the boundary condition can serve as a source that is additional to the spinor matter density.

hep-th↗

arXiv2016

On the chiral separation effect in a slab

We study the influence of boundaries on chiral effects in hot dense relativistic spinor matter in a strong magnetic field which is transverse to bounding planes. The most general set of boundary conditions ensuring the confinement of matter within the bounding planes is considered. We find that, in thermal equilibrium, the nondissipative axial current along the magnetic field is induced, depending on chemical potential and temperature, as well as on a choice of boundary conditions. As temperature increases from zero to large values, a stepwise behaviour of the axial current density as a function of chemical potential is changed to a smooth one; the choice of a boundary condition can facilitate either amplification or diminution of the chiral separation effect. This points at a significant role of boundaries for physical systems with hot dense magnetized relativistic spinor matter, e.g., compact stars, heavy-ion collisions, novel materials known as Dirac and Weyl semimetals.

hep-th↗

arXiv2015

Pressure from the vacuum of confined spinor matter

Charged spinor matter field is quantized in a spatial region bounded by two parallel neutral plates. The most general set of boundary conditions ensuring the confinement of matter within the plates is considered. We study a response of the vacuum of the confined matter to the background uniform magnetic field which is directed orthogonally to the plates. It is proven that, in the case of a sufficiently strong magnetic field, the vacuum pressure onto the plates is positive and independent of the boundary condition, as well as of the distance between the plates.

hep-th↗

arXiv2015

Influence of quantized massive matter fields on the Casimir effect

Charged massive matter fields of spin 0 and 1/2 are quantized in the presence of an external uniform magnetic field in a spatial region bounded by two parallel plates. The most general set of boundary conditions at the plates, that is required by mathematical consistency and the self-adjointness of the Hamiltonian operator, is employed. The vacuum fluctuations of the matter field in the case of the magnetic field orthogonal to the plates are analyzed, and it is shown that the pressure from the vacuum onto the plates is positive and independent of the boundary condition, as well as of the distance between the plates. Possibilities of the detection of this new-type Casimir effect are discussed.

hep-th↗

arXiv2015

The Casimir effect with quantized charged spinor matter in background magnetic field

We study the influence of a background uniform magnetic field and boundary conditions on the vacuum of a quantized charged spinor matter field confined between two parallel neutral plates; the magnetic field is directed orthogonally to the plates. The admissible set of boundary conditions at the plates is determined by the requirement that the Dirac Hamiltonian operator be self-adjoint. It is shown that, in the case of a sufficiently strong magnetic field and a sufficiently large separation of the plates, the generalized Casimir force is repulsive, being independent of the choice of a boundary condition, as well as of the distance between the plates. The detection of this effect seems to be feasible in the foreseeable future.

hep-th↗

arXiv2014

Electromagnetic Field in de Sitter Expanding Universe: Majorana--Oppenheimer Formalism, Exact Solutions in non-Static Coordinates

Tetrad-based generalized complex formalism by Majorana--Oppenheimer is applied to treat electromagnetic field in extending de Sitter Universe in on-static spherically-symmetric coordinates. With the help of Wigner D-functions, we separate angular dependence in the complex vector field E_{j}(t,r)+i B_{j}(t,r) from (t,r)-dependence. The separation parameter arising here instead of frequency ωin Minkowski space-time is quantized, non-static geometry of the de Sitter model leads to definite dependence of electromagnetic modes on the time variable. Relation of 3-vector complex approach to 10-dimensional Duffin-Kemmer-Petiau formalism is considered. On this base, the electromagnetic waves of magnetic and electric type have been constructed in both approaches. In Duffin-Kemmer-Petiau approach, there are constructed gradient-type solutions in Lorentz gauge.

math-ph↗

arXiv2014

The Casimir effect with quantized charged scalar matter in background magnetic field

We study the influence of a background uniform magnetic field and boundary conditions on the vacuum of a quantized charged massive scalar matter field confined between two parallel plates; the magnetic field is directed orthogonally to the plates. The admissible set of boundary conditions at the plates is determined by the requirements that the operator of one-particle energy squared be self-adjoint and positive definite. We show that, in the case of a weak magnetic field and a small separation of the plates, the Casimir force is either attractive or repulsive, depending on the choice of a boundary condition. In the case of a strong magnetic field and a large separation of the plates, the Casimir force is repulsive, being independent of the choice of a boundary condition, as well as of the distance between the plates.

hep-th↗

arXiv2013

Casimir energy and force induced by an impenetrable flux tube of finite radius

A perfectly reflecting (Dirichlet) boundary condition at the edge of an impenetrable magnetic-flux-carrying tube of nonzero transverse size is imposed on the charged massive scalar matter field which is quantized outside the tube. We show that the vacuum polarization effects outside the tube give rise to a macroscopic force acting at the increase of the tube radius (if the magnetic flux is held steady). The Casimir energy and force are periodic in the value of the magnetic flux, being independent of the coupling to the space-time curvature scalar. We conclude that a topological defect of the vortex type can polarize the vacuum of only those quantum fields that have masses which are much less than a scale of the spontaneous symmetry breaking.

hep-th↗

arXiv2013

The Aharonov--Bohm effect in scattering theory

The Aharonov--Bohm effect is considered as a scattering event with nonrelativistic charged particles of the wavelength which is less than the transverse size of an impenetrable magnetic vortex. The quasiclassical WKB method is shown to be efficient in solving this scattering problem. We find that the scattering cross section consists of two terms, one describing the classical phenomenon of elastic reflection and another one describing the quantum phenomenon of diffraction; the Aharonov--Bohm effect is manifested as a fringe shift in the diffraction pattern. Both the classical and the quantum phenomena are independent of the choice of a boundary condition at the vortex edge, providing that probability is conserved. We show that a propagation of charged particles can be controlled by altering the flux of a magnetic vortex placed on their way.

quant-ph↗

arXiv2013

Magnetic Field of Cosmic Strings in the Early Universe

Cosmic strings are topological defects which can be formed as a result of phase transitions with a spontaneous symmetry breaking in the early Universe. The possibility of the generation of a magnetic field around a cosmic string on the Grand Unification energy scale (GUT scale) in the early Universe immediately after the termination of the deconfinement-confinement phase transition has been analyzed. It is found that a circular current and a magnetic field directed along the string are induced around the string in the vacuum of a pseudoscalar matter consisting of charged pions. We also have studied the interaction between the magnetic flux tube surrounding the string (the string magnetosphere) and the cosmic plasma in the early Universe. A possibility of magnetization of the cosmic plasma surrounding the string owing to its interaction with the string magnetic field has been analyzed.

astro-ph.CO↗

arXiv2013

Casimir force induced on a plane by an impenetrable flux tube of finite radius

hep-th↗

arXiv2012

The Aharonov-Bohm effect in scattering of short-wavelength particles

Quantum-mechanical scattering of nonrelativistic charged particles by a magnetic vortex of nonzero transverse size is considered. We show that the flux of the vortex serves as a gate for the strictly forward propagation of particles with short, as compared to the transverse size of the vortex, wavelengths; this effect is the same for a penetrable vortex as for an impenetrable one. A possibility for the experimental detection of the scattering Aharonov-Bohm effect is discussed.

quant-ph↗

arXiv2012

Induced vacuum energy-momentum tensor in the background of a cosmic string

A massive scalar field is quantized in the background of a cosmic string which is generalized to a static flux-carrying codimension-2 brane in the locally flat multidimensional space-time. We find that the finite energy-momentum tensor is induced in the vacuum. The dependence of the tensor components on the brane flux and tension, as well as on the coupling to the space-time curvature scalar, is comprehensively analyzed. The tensor components are holomorphic functions of space dimension, decreasing exponentially with the distance from the brane. The case of the massless quantized scalar field is also considered, and the relevance of Bernoulli's polynomials of even order for this case is discussed.

hep-th↗

arXiv2011

Vacuum energy induced by an impenetrable flux tube of finite radius

We consider the effect of the magnetic field background in the form of a tube of the finite transverse size on the vacuum of the quantized charged massive scalar field which is subject to the Dirichlet boundary condition at the edge of the tube. The vacuum energy is induced, being periodic in the value of the magnetic flux enclosed in the tube. Our previous study in J. Phys. A: Vol.43, 175401 (2010) is extended to the case of smaller radius of the tube and larger distances from it. The dependence of the vacuum energy density on the distance from the tube and on the coupling to the space-time curvature scalar is comprehensively analyzed.

hep-th↗