arXiv subjects

I. L. Zhogin

Publications and source records attributed to I. L. Zhogin.

13 recordsLinked to original sources

arXiv2023

Extragalactic TeV Photons and the Zero-point Vibration Spectrum Limit

There are observations indicating a possible anomalous transparency of intergalactic space (filled with infrared background light) for extragalactic gamma-rays of very high energy (> 100 GeV). The anomaly is usually associated with effects of some new physics. However, another explanation is possible -- as a manifestation relating to a cut-off of the zero-point vibration spectrum. It is assumed that this boundary U_{ZV} is isotropic in the reference frame, where the cosmic microwave background (CMB) radiation is isotropic, and an estimate is obtained: U_{ZV} ~7.4 TeV. The presence of a ZV boundary also leads to an increased beta decay time of accelerated particles with the Lorentz factor > 50. It is widely believed that the ZV-spectrum continues up to the Planck energy. There is, however, a 5D variant of the Absolute Parallelism theory (AP), free from singularities of solutions, where a large characteristic length L appears, which determines the thickness of expanding spherical S^3-shell (the cosmological solution as the longitudinal wave along the radius) in co-moving co-ordinates. Newton's Law 1/r^2 is replaced by 1/r at distances exceeding L, and the Planck length (a composite parameter) `arises' from L when switching to the conventional energy-momentum scale. The theory features are briefly exposed -- description of 15 polarizations (degrees of freedom), the energy-momentum tensor (in prolonged 4th order equations), topological charges and quasi-charges of localized field configurations.

hep-ph↗

arXiv2022

One more fitting (D=5) of Supernovae redshifts

Supernova Ia redshifts are fitted with a simple $5D$ model: the galaxies are assumed to be enclosed in a giant $S^3$-spherical shell of significant thickness, which expands (ultra)relativisticaly in Minkowski (1+4)$D$-space. This model, as compared with the kinematic (1+3)$D$ Milne cosmological model (which was reinvented by Prof Farley), goes in line with the Copernican principle: any galaxy observes the same isotropic distribution of distant galaxies and supernovae, as well as the same Hubble plot of SN Ia distance modulus $μ$ vs redshift $z$. A good fit is obtained (no free parameters); it coincides with the Milne model (empty model) at low $z$, while shows some more luminosity at high $z$, leading to 1% decrease in the true distance modulus (and 50% increase in luminosity) at $z\sim2$. The model proposed can be also interpreted as a sort of FLRW-model with the scale factor $a(t)=t/t_0$; this could hardly be a solution of general relativity (without inventing some super-dark energy with $w=-1/3$, a sort of dark curvature); 5$D$ GR is also unsuitable -- it has no longitudinal polarization. However, there still exists the other theory (with $D=5$ and no singularities in solutions), the other game in the town, which seems to be able to do the job.

gr-qc↗

arXiv2022

Absolute Parallelism: Spherical Symmetry and Singularities

Observing the list of compatible second order equations of Absolute Parallelism (AP) found by Einstein and Mayer (they used D=4), we choose the one-parameter class of equations which take on a 3-linear form (when contra-frame density of some weight is in use). Spherically symmetric solutions to these equations are considered, and we try not to add any delta-sources (ie, $δ(x)$-sources of unknown nature) during integrations allowed due to this high symmetry. Using two different ways to fix the radius and time, we have found that only non-static solutions (except for trivial one, of course) are possible. If D=5, such solutions, looking like a single wave moving along the radius, could serve as an expanding cosmological model (with a simple Hubble diagram). With one coordinate choice (gauge), a single second order equation remains and there exist spherically symmetric solutions with arising singularities. On the other hand, a more reasonable (covariant) choice of the radius and time reduces the problem to a system of two first order equations looking like Chaplygin gas dynamics, where solutions are seemingly free of emerging singularities and gradient catastrophe.

gr-qc↗

arXiv2011

Absolute parallelism, modified gravity, and suppression of gravitational short waves

There is a unique variant of Absolute Parallelism, which is very simple as it has no free parameters: nothing (nor D=5) can be changed if to keep the theory safe from emerging singularities of solutions. On the contrary, eternal solutions of this theory, due to the linear instability of the trivial solution, should be of great complexity which can in some scenarios (with a set of slowly varying parameters of solutions) provide a few phenomenological models including a modified (better to say, new or another) gravity and an expanding-shell cosmology (the longitudinal polarization gives the anti-Milne model). The former looks (mostly) like a variant of tensor-Ricci-squared gravity on a brane of a huge scale L along the extra-dimension. The correction to Newton's law of gravity, which depends in this theory on two parameters (bi-Laplace equation) and behaves as 1/r on large scales, r>L (kpc>L>pc), can start from zero (the Rindler term vanishes) if a constraint is imposed on these parameters. On further consideration, one can conclude that generation of gravitational `short' waves, λ<L, is inhibited in this new gravity.

gr-qc↗

arXiv2011

On relevance of modified gravities

It is shown that modified gravity theories with a Lagrangian composed of the three quadratic invariants of the Riemann curvature tensor are not appropriate. The field equations are either incompatible and/or irregular [like f(R)-gravities], or, if compatible, lead to the linear instability of polarizations relating to the Weyl tensor. A more relevant modification is the frame field theory, namely the best and unique variant of Absolute Parallelism; it has no free parameters (D=5 is a must) and no singularities arising in solutions. I sketch few remarkable features of this theory.

gr-qc↗

arXiv2010

Old and new research on the Absolute Parallelism theory

Compatible equations, Singularities of solutions, Topological charges and quasi-charges. PhD thesis (translated frorm Russian). The book shows the sights of Absolute Parallelism (AP), and contains useful information on the problem of singularities, compatibility theory, homotopy groups (also relative and k-ad), topological quasi-charge groups and their morphisms. AP is a single (frame) field theory proposed by Einstein some 80 years ago; it embraces symmetries of both Special and General Relativity. The compatibility theory, if applied to the cases when the frame matrix degenerates, gives a covariant test on singularities of solutions. This gives a single variant (missed in Einstein-Mayer's list of compatible equations), the unique 5D equation (nothing, nor D, can be changed), which solutions are free of emerging singularities. SO4-symmetrical nonstationary solutions give rise to a cosmological model (relativistic surfing; anti-Milne model in FRW framework) with a specific reduction of the extra-dimension. Topological classification of localized field configurations, combinatorics of topological quasi-charges (quanta), is discussed in an attempt to imagine the Standard Model (and quantum theory itself; and, perhaps, to make some qualitative predictions, like the absence of spin zero elementary quanta).

gr-qc↗

arXiv2010

Anisomagnetic quasi-achromats with small effective emittance

Quasi-achromat lattices (small dispersion is allowed in their straight sections, between their cells) are considered; in a cell, there are bending magnets of two kinds, of unequal magnetic field. Minimization of the effective emittance is carried out by the following algorithm (which follows Teng, and partly Lee). (1) Every inner dipole's contribution to the natural emittance is minimized with respect to all optics parameters (relating to dispersion and beta-function), except for the shift parameter, s_0, which specifies the interval between the beta-function minimum and the center of a magnet; for a side bending magnet, its contribution to an integral relating to the effective emittance (the relation uses the fact that the arithmetic mean majorizes the geometric mean) is minimized. (2) The other parameters of dipoles (fields, lengths or angles ratios, shifts) are restricted with the boundary conditions: the equality of Courant-Snyder invariants on the exit from a magnet and on the entrance to the following one. (3) The minimum of effective emittance and the last free parameters (two or three) can be found by computation. The accuracy of this method falls with decreasing of the number of internal dipoles in a cell, and still the isomagnetic Tanaka-Ando minimum (for the modified DBA*-lattice which has no inner dipoles) is reproduced with accuracy better than half a percent. If the number of dipoles per cell does not exceed four, the smallest effective emittance (14% lower than TA-limit) is achieved for QBA**-lattice where all dipoles have nonzero shifts.

physics.acc-ph↗

arXiv2008

Application of introduced nano-diamonds for the study of carbon condensation during detonation of high explosives

This paper describes the experimental studies of the formation of nano-diamonds during detonation of TNT/RDX 50/50 mixture with small-angle x-ray scattering (SAXS) method at a synchrotron radiation beam on VEPP-3 accelerator. A new experimental method with introduction of nano-diamonds into the explosive has been applied. Inclusion of the diamonds obtained after detonation into the TNT and RDX explosives allows modelling of the case of instant creation of nano-diamonds during detonation.

cond-mat.other↗

arXiv2008

Tri-crystal fixed exit monochromator

It is proposed a novel design of an X-ray monochromator which uses three crystals. The exit beam turns in horizontal plane on the angle $2α$ with respect to the incoming beam. So, this kind of monochromator is suitable for side beam-lines; several tunable beam-lines can be built for a one fan beam of synchrotron radiation (from wiggler or bending magnet). In contrast to the double-crystal scheme of general position considered previously (which also suitable for side beam-lines), the new variant does not lead to a tilt of exit beam profile.

physics.ins-det↗

arXiv2008

Detector for imaging of explosions: present status and future prospects with higher energy X-rays

The detector for imaging of explosions (DIMEX) is in operation at the synchrotron radiation (SR) beam-line at VEPP-3 electron ring at Budker INP since 2002. DIMEX is based on one-coordinate gas ionization chamber filled with Xe-CO2(3:1) mixture at 7atm, and active Frisch-grid made of Gas Electron Multiplier (GEM). The detector has spatial resolution of ~0.2mm and dynamic range of ~100 that allows to realize the precision of signal measurement at a percent level. The frame rate can be tuned up to 8 MHz (125 ns per image) and up to 32 images can be stored in one shot. At present DIMEX is used with the X-ray beam from 2T wiggler that has ~20 keV average energy. Future possibility to install similar detector at the SR beam-line at VEPP-4 electron ring is discussed.

physics.ins-det↗

arXiv2007

Extrasolar scale change in Newton's Law from 5D `plain' R^2-gravity

Galactic rotation curves and lack of direct observations of Dark Matter may indicate that General Relativity is not valid (on galactic scale) and should be replaced with another theory. There is the only variant of Absolute Parallelism which solutions are free of arising singularities, if D=5 (there is no room for changes). This variant does not have a Lagrangian, nor match GR: an equation of `plain' R^2-gravity (ie without R-term) is in sight instead. Arranging an expanding O_4-symmetrical solution as the basis of 5D cosmological model, and probing a universal_function of mass distribution (along very-very long the extra dimension) to place into bi-Laplace equation (R^2 gravity), one can derive the Law of Gravitation: 1/r^2 transforms to 1/r with distance (not with acceleration).

astro-ph↗

arXiv2007

Topological charges and quasi-charges in Absolute Parallelism

Absolute Parallelism (AP) has many interesting features: large symmetry group of equations; field irreducibility with respect to this group; vast list of consistent second order equations not restricted to Lagrangian ones. There is the variant of AP which solutions are free of arising singularities if D=5; in this case AP acquires topological features of nonlinear sigma-model. Starting with topological charge, one can also introduce the topological quasi-charge groups for field configurations having some symmetry. For 4D, considering symmetrical equipped 0-(sub)manifolds in R^3, we find QC-groups for some symmetries (subsets of O_3) and describe their morphisms. Differential 3-form of topological charge (dual to topological current) is derived, as well as O_3-quasi-charge 1-form. Results of topological classification of symmetric configurations in 5D case (alighting on evident parallels with the Standard Model combinatorics of fundamental particles) are announced. An example of SO_2-symmetric configuration is considered; (quasi-)charge forms (self-dual and anti-self-dual) are obtained. In conclusion, we propose a variant of experiment with single photon interference (or with bi-photon non-local correlations) which should verify a possible non-local (spaghetti-like) 5D ontology of particles.

gr-qc↗

arXiv2002

Trilinear generally covariant equations of AP

Field equations for n-frames h_a{}^μthat are possible in the theory of absolute parallelism (AP) are considered. The methods of compatibility (or formal integrability) theory enable us to find the non-Lagrangian equation having unusual kind of compatibility conditions, guaranteed by two (not one) identities. This 'unique equation' was not noted explicitly in the classification by Einstein and Mayer of compatible second order equations of AP. It is shown that some equations of AP (including 'unique equation') can be written in a trilinear form that contains only the matrix of frame density (of some weight) H_a{}^μand its derivatives and not inverse (coframe density) matrix. The equations are still regular and involutive for degenerate but finite matrices H_a{}^μif rank H_a{}^μ> 1.

gr-qc↗