arXiv subjects

A. A. Kirillov

Publications and source records attributed to A. A. Kirillov.

At least 37 records · Page 2Linked to original sources

arXiv2014

Signatures of primordial black hole dark matter

The nonbaryonic dark matter of the Universe is assumed to consist of new stable forms of matter. Their stability reflects symmetry of micro world and mechanisms of its symmetry breaking. In the early Universe heavy metastable particles can dominate, leaving primordial black holes (PBHs) after their decay, as well as the structure of particle symmetry breaking gives rise to cosmological phase transitions, from which massive black holes and/or their clusters can originate. PBHs can be formed in such transitions within a narrow interval of masses about $10^{17}$g and, avoiding severe observational constraints on PBHs, can be a candidate for the dominant form of dark matter. PBHs in this range of mass can give solution of the problem of reionization in the Universe at the redshift $z\sim 5... 10$. Clusters of massive PBHs can serve as a nonlinear seeds for galaxy formation, while PBHs evaporating in such clusters can provide an interesting interpretation for the observations of point-like gamma-ray sources. Analysis of possible PBH signatures represents a universal probe for super-high energy physics in the early Universe in studies of indirect effects of the dark matter.

astro-ph.CO↗

arXiv2014

On the possibility of the generation of an artificial wormhole

We model spacetime foam by a gas of virtual wormholes. Then applying an external field one may change the density of virtual wormholes and try to organize a wormhole-like structure in space. The relation between an additional distribution of virtual wormholes and the external field is considered for the homogeneous case. We show that the external fields suppress the density of virtual wormholes which sets an obstruction for creating an actual wormhole in a straightforward fashion. We also present a rough idea of a more complicated model for the artificial creation of a wormhole.

gr-qc↗

arXiv2013

Dark energy from the gas of wormholes

We assume the space-time foam picture in which the vacuum is filled with a gas of virtual wormholes. It is shown that virtual wormholes form a finite (of the Planckian order) value of the energy density of zero-point fluctuations. However such a huge value is compensated by the contribution of virtual wormholes to the mean curvature and the observed value of the cosmological constant is close to zero. A non-vanishing value appears due to the polarization of vacuum in external classical fields. In the early Universe some virtual wormholes may form actual ones. We show that in the case of actual wormholes vacuum polarization effects are negligible while their contribution to the mean curvature is apt to form the observed dark energy phenomenon. Using the contribution of wormholes to dark matter and dark energy we find estimates for characteristic parameters of the gas of wormholes.

astro-ph.CO↗

arXiv2012

Gamma-ray evidences of the dark matter clumps

We discuss the possibility of identification of point-like gamma-ray sources (PGS) with small scale dark matter (DM) clumps in our Galaxy. Gamma-rays are supposed to originate from annihilation of DM particles in the clumps, where annihilation rate is supposed to be enhanced, besides higher density, due to smaller relative velocities $v$ of DM particles. We parameterized the annihilation cross section $σ_\text{ann}(v)$ in the form of an arbitrary power law dependence on the relative velocity $v$ with/without factor of Sommerfeld-Gamow-Sakharov, implying existence of a new Coulomb-like interaction. Adopting different parameters of cross section and clump, satisfying condition $Ω\lesssim 0.2$ on density of DM particles of question, they are constrained from comparison with Fermi/LAT data on unidentified PGS as well as on diffuse $γ$-radiation; results are applied to concrete DM candidates. Such analysis is found to be sensitive enough to existing uncertainty in the density profiles of DM in the clump what can provide a tool for their test. Also we discuss possibilities when gamma-radiating clump changes visibly its position on celestial sphere and it is seen as a spatially extended gamma-source (EGS), what can be probed in future experiments like Gamma-400.

astro-ph.HE↗

arXiv2012

Clusters of Black Holes as Point-Like Gamma-ray Sources

The possibility of identifying some of Galactic gamma-ray sources as clusters of primordial black holes is discussed. The known scenarios of supermassive black hole formation indicate the multiple formation of lower-mass black holes. Our analysis demonstrates that due to Hawking evaporation the cluster of black holes with masses about $10^{15}$ g could be observed as a gamma-ray source. The total mass of typical cluster is $\sim 10 M_\odot$. Detailed calculations have been performed on the basis of specific model of primordial black hole formation.

astro-ph.HE↗

arXiv2012

Emergence of symmetries

The mechanism of symmetry formation is discussed in the framework of multidimensional gravity. It is shown that this process is strictly connected to the entropy decrease of compact space. The existence of low energy symmetries is not postulated from the beginning. They could be absent during the inflationary stage under certain conditions discussed in the paper.

gr-qc↗

arXiv2012

Artificial Wormhole

It is shown that recently reported result by the OPERA Collaboration (arXive:1109.4897) of an early arrival time of muon neutrinos with respect to the speed of light in vacuum does not violate standard physical laws. We show that vacuum polarization effects in intensive external fields may form a wormhole-like object. The simplest theory of such an effect is presented and basic principles of formation of an artificial wormhole are also considered.

astro-ph.CO↗

arXiv2011

On Scattering of Electromagnetic Waves by a Wormhole

We consider scattering of a plane electromagnetic wave by a wormhole. It is found that the scattered wave is partially depolarized and has a specific interference picture depending on parameters of the wormhole and the distance to the observer. It is proposed that such features can be important in the direct search of wormholes.

astro-ph.CO↗

arXiv2010

Density perturbations in the gas of wormholes

The observed dark matter phenomenon is attributed to the presence of a gas of wormholes. We show that due to topological polarization effects the background density of baryons generates non-vanishing values for wormhole rest masses. We infer basic formulas for the scattering section between baryons and wormholes and equations of motion. Such equations are then used for the kinetic and hydrodynamic description of the gas of wormholes. In the Newtonian approximation we consider the behavior of density perturbations and show that at very large distances wormholes behave exactly like heavy non-baryon particles, thus reproducing all features of CDM models. At smaller scales (at galaxies) wormholes strongly interact with baryons and cure the problem of cusps. We also show that collisions of wormholes and baryons lead to some additional damping of the Jeans instability in baryons.

astro-ph.CO↗

arXiv2009

On topological bias of discrete sources in the gas of wormholes

The model of space in the form of a static gas of wormholes is considered. It is shown that the scattering on such a gas gives rise to the formation of a specific diffuse halo around every discrete source. Properties of the halo are determined by the distribution of wormholes in space and the halo has to be correlated with the distribution of dark matter. This allows to explain the absence of dark matter in intergalactic gas clouds. Numerical estimates for parameters of the gas of wormholes are also obtained.

astro-ph.CO↗

arXiv2009

Properties and application of the form $A\cdot exp(-(x-c)^2/(a(x-c)+2b^2))$ for investigation of ultra high energy cascades

The form $A\cdot exp(-(x-c)^2 /(a(x-c)+2b^2))$ is an asymmetric distribution intermediate between the normal and exponential distributions. Some specific properties of the form are presented and methods of approximation are offered. Appropriate formulae and table are presented. The practical problems of approximation by the form are discussed with connection to the quality of original data. Application of the methods is illustrated by using in the problem of calculating and studying distribution function of maximum ultra high energy atmospheric showers. Relationship with exponential and normal distributions makes usage of the form to be effective in practice.

physics.data-an↗

arXiv2008

Instability of fermions with respect to topology fluctuations

We extend our sum over topologies formula to fermions. We show that fermionic fields display an instability with respect to topology fluctuations. We present some phenomenological arguments for a modification of the action in the case of fermions and discuss possible applications.

hep-th↗

arXiv2008

On the behavior of bosonic systems in the presence of topology fluctuations

The behavior of bosonic systems in the presence of space-time foam is analyzed within the simplistic model of a set of scalar fields on a flat background. We discuss the formula for the path integral which allows to account for the all possible topologies of spacetime. We show that the proper path integral originates from the parastatistics suggested first by H.S. Green and that it defines a cutoff for the field theory.

hep-th↗

arXiv2008

Spacetime foam

Spacetime foam is analyzed within the simplistic model of a set of scalar fields on a flat background. We suggest the formula for the path integral which allows to account for the all possible topologies of spacetime. We show that the proper path integral defines a cutoff for the field theory. The form of the cutoff is fixed by the field theory itself and has no free additional parameters. New features of the Feynman diagram technic are outlined and possible applications in quantum gravity are discussed.

gr-qc↗

arXiv2008

Propagation of cosmic rays in the foam-like Universe

The model of a classical spacetime foam is considered, which consists of static wormholes embedded in Minkowski spacetime. We examine the propagation of particles in such a medium and demonstrate that a single thin ray undergoes a specific damping in the density of particles depending on the traversed path and the distribution of wormholes. The missing particles are scattered around the ray. Wormholes was shown to form DM halos around point-like sources. Therefore, the correlation predicted between the damping and the amount of DM can be used to verify the topological nature of Dark Matter.

astro-ph↗

arXiv2007

Dark Matter from a gas of wormholes

The simplistic model of the classical spacetime foam is considered, which consists of static wormholes embedded in Minkowski spacetime. We explicitly demonstrate that such a foam structure leads to a topological bias of point-like sources which can equally be interpreted as the presence of a dark halo around any point source. It is shown that a non-trivial halo appears on scales where the topological structure possesses a local inhomogeneity, while the homogeneous structure reduces to a constant renormalization of the intensity of sources. We also show that in general dark halos possess both (positive and negative) signs depending on scales and specific properties of topological structure of space.

astro-ph↗

arXiv2007

Foam-like structure of the Universe

On the quantum stage spacetime had the foam-like structure. When the Universe cools, the foam structure tempers and does not disappear. We show that effects caused by the foamed structure mimic very well the observed Dark Matter phenomena. Moreover, we show that in a foamed space photons undergo a chaotic scattering and together with every discrete source of radiation we should observe a diffuse halo. We show that the distribution of the diffuse halo of radiation around a point-like source repeats exactly the distribution of dark matter around the same source, i.e. the DM halos are sources of the diffuse radiation.

astro-ph↗

arXiv2007

Effects related to spacetime foam in astrophysics

On the quantum stage spacetime had the foam-like structure. When the Universe cools the foam structure temperes and therefore the Friedman model represents only the mean picture. We show that effects of the foamed structure we observe now as the Dark Matter and Dark Energy phenomena. We also show that free particles undergo a specific scattering on the foam-like structure. This explains the origin of the diffuse component of the X-ray background and gives a rather simple picture for the origin of Gamma-ray bursts.

astro-ph↗