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Vladimir Dzhunushaliev

Publications and source records attributed to Vladimir Dzhunushaliev.

At least 91 records · Page 5Linked to original sources
arXiv2015

Cosmological constant, supersymmetry, nonassociativity, and Big Numbers

The nonassociative generalization of supersymmetry is considered. It is shown that the associator of four supersymmetry generators has the coefficient $\sim \hbar/ \ell_0^2$ where $\ell_0$ is some characteristic length. Two cases are considered: (a) $\ell_0^{-2}$ coincides with the cosmological constant; (b) $\ell_0$ is the classical radius of electron. It is also shown that the scaled constant is of the order of $10^{-120}$ for the first case and $10^{-30}$ for the second case. The possible manifestation and smallness of nonassociativity is discussed.

gr-qc↗
arXiv2014

Boson Stars with Nontrivial Topology

We construct boson star solutions in the presence of a phantom field, allowing for a nontrivial topology of the solutions. The wormholes residing at the core of the configurations lead to a number of qualitative changes of the boson star solutions. In particular, the typical spiraling dependence of the mass and the particle number on the frequency of the boson stars is lost. Instead, the boson stars with nontrivial topology approach a singular configuration in the limit of vanishing frequency. Depending on the value of the coupling constant, the wormhole geometry changes from a single throat configuration to a double throat configuration, featuring a belly inbetween the two throats. Depending on the mass of the boson field and its self-interaction, the mass and the size of these objects cover many orders of magnitude, making them amenable to various astrophysical observations. A stability analysis reveals, that the unstable mode of the Ellis wormhole is retained in the presence of the bosonic matter. However, the negative eigenvalue can get very close to zero, by tuning the parameters of the self-interaction potential appropriately.

gr-qc↗
arXiv2014

Propagation of gravitational waves in the nonperturbative spinor vacuum

The propagation of gravitational waves on the background of a nonperturbative vacuum of a spinor field is considered. It is shown that there are several distinctive features in comparison with the propagation of plane gravitational waves through empty space: there exists the fixed phase difference between the $h_{yy,zz}$ and $h_{yz}$ components of the wave; the phase and group velocities of gravitational waves are not equal to the velocity of light; the group velocity is always less than the velocity of light; under some conditions the gravitational waves are either damped or absent; for given frequency, there exist two waves with different wave vectors. We also discuss the possibility of experimental verification of the obtained effects as a tool to investigate nonperurbative quantum field theories.

gr-qc↗
arXiv2014

Cosmological constant and Euclidean space from nonperturbative quantum torsion

Heisenberg's nonperturbative quantization technique is applied to the nonpertrubative quantization of gravity. An infinite set of equations for all Green's functions is obtained. An approximation is considered where: (a) the metric remains as a classical field; (b) the affine connection can be decomposed into classical and quantum parts; (c) the classical part of the affine connection are the Christoffel symbols; (d) the quantum part is the torsion. Using a scalar and vector fields approximation it is shown that nonperturbative quantum effects gives rise to a cosmological constant and an Euclidean solution.

gr-qc↗
arXiv2014

Hiding a neutron star inside a wormhole

We consider neutron-star-plus-wormhole configurations supported by a massless ghost scalar field. The neutron fluid is modeled by an anisotropic equation of state. When the central energy density of the fluid is of comparable magnitude to the one of the scalar field, configurations with an equator at the center and a double throat arise. These double-throat wormholes can be either partially or completely filled by the neutron fluid. In the latter case, the passage of light - radiated by the neutron matter - through these wormholes is studied. A stability analysis indicates that all considered configurations are unstable with respect to linear perturbations, independent of whether the fluid is isotropic or anisotropic.

gr-qc↗
arXiv2014

Wormhole solutions supported by interacting dark matter and dark energy

We show that the presence of a nonminimal interaction between dark matter and dark energy may lead to a violation of the null energy condition and to the formation of a configuration with nontrivial topology (a wormhole). In this it is assumed that both dark matter and dark energy satisfy the null energy condition, a violation of which takes place only in the inner high-density regions of the configuration. This is achieved by assuming that, in a high-density environment, a nonminimal coupling function changes its sign in comparison with the case where dark matter and dark energy have relatively low densities which are typical for a cosmological background. For this case, we find regular static, spherically symmetric solutions describing wormholes supported by dark matter nonminimally coupled to dark energy in the form of a quintessence scalar field.

gr-qc↗
arXiv2014

Modified gravity from the quantum part of the metric

It is shown that if a metric in quantum gravity can be decomposed as a sum of classical and quantum parts then Einstein quantum gravity looks approximately like modified gravity with a nonminimal interaction between gravity and matter.

gr-qc↗
arXiv2013

Rotating Wormholes in Five Dimensions

We consider rotating Lorentzian wormholes with a phantom field in five dimensions. These wormhole solutions possess equal angular momenta and thus represent cohomogeneity-1 configurations. For a given size of the throat, the angular momenta are bounded by the value of the corresponding extremal Myers-Perry black hole, which represents the limiting configuration. With increasing angular momenta the throat becomes increasingly deformed. At the same time, the violation of the null energy condition decreases to zero, as the limiting configuration is approached. Symmetric wormhole solutions satisfy a Smarr-like relation, which is analogous to the Smarr relation of extremal black holes. A stability analysis shows that the unstable mode of the static wormholes solutions vanishes when the angular momentum exceeds some critical value.

gr-qc↗
arXiv2013

Chameleon dark matter stars

We consider static, spherically symmetric equilibrium configurations consisting of fermionic dark matter nonminimally coupled to dark energy in the form of a quintessence scalar field. With the scalar field coupling function, the form of which is taken to meet cosmological observations, we estimate the effect of such a nonminimal coupling on the properties of dark matter compact configurations. We show that the masses and sizes of the resulting chameleon dark matter stars are smaller than those of systems with no field present.

astro-ph.SR↗
arXiv2013

Kaluza-Klein wormholes with the compactified fifth dimension

We consider wormhole solutions in five-dimensional Kaluza-Klein gravity in the presence of a massless ghost four-dimensional scalar field. The system possesses two types of topological nontriviality connected with the presence of the scalar field and of a magnetic charge. Mathematically, the presence of the charge appears in the fact that the $S^3$ part of a spacetime metric is the Hopf bundle $S^3 \rightarrow S^2$ with fibre $S^1$. We show that the fifth dimension spanned on the sphere $S^1$ is compactified in the sense that asymptotically, at large distances from the throat, the size of $S^1$ is equal to some constant, the value of which can be chosen to lie, say, in the Planck region. Then, from the four-dimensional point of view, such a wormhole contains a radial magnetic (monopole) field, and an asymptotic four-dimensional observer sees a wormhole with the compactified fifth dimension.

gr-qc↗
arXiv2013

Mixed neutron-star-plus-wormhole systems: Linear stability analysis

We consider configurations consisting of a neutron star with a wormhole at the core. The wormhole is held open by a ghost scalar field with a quartic coupling. The neutron matter is described by a perfect fluid with a polytropic equation of state. We obtain static regular solutions for these systems. A stability analysis, however, shows that they are unstable with respect to linear perturbations.

gr-qc↗
arXiv2013

Singularity-free model of electric charge in physical vacuum: Non-zero spatial extent and mass generation

We propose a model of a spinless electrical charge as a self-consistent field configuration of the electromagnetic (EM) field interacting with a physical vacuum effectively described by the logarithmic quantum Bose liquid. We show that, in contrast to the EM field propagating in a trivial vacuum, a regular solution does exist, and both its mass and spatial extent emerge naturally from dynamics. It is demonstrated that the charge and energy density distribution acquire Gaussian-like form. The solution in the logarithmic model is stable and energetically favourable, unlike that obtained in a model with a quartic (Higgs-like) potential.

hep-th↗
arXiv2013

Nonperturbative quantization and turbulence: the comparison

The comparison of calculations methods in nonperturbative quantum fields theory and turbulence theory is made. The main result is that in both cases there is an infinite equations set. In the first case it is the equations set for Green's functions and in the second case it is the equations set for cumulants. It allows us to use similar mathematical methods to solve problems in nonperturbative quantum field theory and turbulence modeling. A closure problem of truncation of the infinite equations set is discussed.

hep-ph↗
arXiv2013

SU(3) flux tube gluon condensate

The distribution of a gluon condensate in a flux tube is calculated. The result is that the chromoelectric fields are confined with a surrounding coset chromomagnetic field. Such picture presents the concrete realization of dual QCD model in a scalar model of the flux tube. In the scalar model the SU(3) gauge fields are separated on two parts: (1) is the $SU(2) \subset SU(3)$ subgroup, (2) is the coset $SU(3) / SU(2)$. The SU(2) degrees of freedom are almost classical and the coset degrees of freedom are quantum ones. A nonperturbative approach for the quantization of the coset degrees of freedom is applied. In this approach 2-point Green's function is a bilinear combination of scalar fields and 4-point Green's function is the product of 2-points Green's functions. The gluon condensate is an effective Lagrangian describing the SU(2) gauge field with broken gauge symmetry and coupling with the scalar field. Corresponding field equations give us the flux tube.

hep-ph↗
arXiv2013

Blind physics: a catalogue of unverified hypotheses

Some hypotheses in modern theoretical physics that have not any experimental verification are listed. The goal of the paper is not to criticize or be lawyers any of these hypotheses. The purpose is focus physicists attention on that now there are too much hypotheses which are not confirmed experimentally.

physics.gen-ph↗
arXiv2012

Mass gap in scalar glueball model

On the basis of a nonperturbative scalar model of gluon condensate the model of glueball is considered. Two scalar fields describe quantum fluctuations of gauge potential components belonging to a small subgroup $SU(2) \subset SU(3)$ and a coset $SU(3) / SU(2)$ correspondingly. In this consideration nonperturbative quantum corrections appear. The corrections are connected with a hidden structure of operators of strongly interacting gauge field. A regular solution for two scalar fields is obtained. The solution is a ball filled with quantum fluctuations of SU(3) gauge field. The space distribution of the dispersion of quantum fluctuations of gauge potential is presented.

hep-ph↗