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M. Yu. Konstantinov

Publications and source records attributed to M. Yu. Konstantinov.

12 recordsLinked to original sources
arXiv2001

Measurement of the gravitational constant $G$ in space (Project SEE): sensitivity to orbital parameters and space charge effect

We describe some new estimates concerning the recently proposed SEE (Satellite Energy Exchange) experiment for measuring the gravitational interaction parameters in space. The experiment entails precision tracking of the relative motion of two test bodies (a heavy "Shepherd", and a light "Particle") on board a drag-free space capsule. The new estimates include (i) the sensitivity of Particle trajectories and G measurement to the Shepherd quadrupole moment uncertainties; (ii) the measurement errors of G and the strength of a putative Yukawa-type force whose range parameter λmay be either of the order of a few meters or close to the Earth radius; (iii) a possible effect of the Van Allen radiation belts on the SEE experiment due to test body electric charging. The main conclusions are that (i) the SEE concept may allow one to measure G with an uncertainty smaller than 10^{-7} and a progress up to 2 orders of magnitude is possible in the assessment of the hypothetic Yukawa forces and (ii) van Allen charging of test bodies is a problem of importance but it may be solved by the existing methods.

gr-qc↗
arXiv2000

See Project for Testing Gravity in Space: Current Status and New Estimates

We describe some new estimates concerning the recently proposed SEE (Satellite Energy Exchange) experiment for measuring the gravitational interaction parameters in space. The experiment entails precision tracking of the relative motion of two test bodies (a heavy "Shepherd", and a light "Particle") on board a drag-free capsule. The new estimates include (i) the sensitivity of Particle trajectories and G measurement to the Shepherd quadrupole moment uncertainties; (ii) the measurement errors of G and the strength of a putative Yukawa-type force whose range parameter $λ$ may be either of the order of a few metres or close to the Earth radius; (iii) a possible effect of the Van Allen radiation belts on the SEE experiment due to test body electric charging

gr-qc↗
arXiv1998

Superluminal propagation of light in gravitational field and non-causal signals: some comments

We examine the recent statement by A. Dolgov and I. Novikov that superluminal propagation of light, which is induced by the quantum corrections to the photon propagation in gravitational field, permits non-causal signal propagation. For this purpose we examine the possibility of the existence of non-causal signals in the model case, when characteristic cone of the signal is outside the usual light cone in Minkowski space-time, as it take place in the case of the photon propagation in gravitation field with quantum corrections taking into account. In such model the signal propagates along invariant intervals. It is shown that there are no non-causal signals in the considered model. The recent statement of A. Dolgov and I. Novikov was obtained by using additional supposition that velocity of the signal with respect to the emitter is independent from its motion. Such supposition does not valid in the case of the photon propagation in gravitational field.

gr-qc↗
arXiv1998

Causality properties of topologically nontrivial space-time models

Some problems of the space-time causal structure are discussed using models with traversable wormholes. For this purpose the conditions of traversable wormhole matching with the exterior space-time are considered in detail and a mixed boundary problem for the Einstein equations is formulated and analyzed. The influence of these matching conditions on the space-time properties and causal structure is analyzed. These conditions have a non-dynamical nature and cannot be determined by any physical process. So, the causality violation cannot be a result of dynamical evolution of some initial hypersurface. It is also shown that the same conditions which determine the wormhole joining with the outer space provide the self-consistency of solutions and the absence of paradoxes in the case of causality violation.

gr-qc↗
arXiv1997

Mixed Boundary Problem for the Traversable Wormhole Models

The conditions of the traversable wormhole joining with the exterior space-time are considered in details and the mixed boundary problem for the Einstein equations is formulated. It is shown that, in opposite to some declarations, the conditions of the wormhole joining with the exterior space-time have non-dynamical nature and can not be defined by the physical processes. The role of these conditions in the formation of the causal structure of space-time is analyzed. It is shown that the causal structure of the wormhole-type space-time models is independent from both the interior and exterior energy-momentum tensors. This statement is illustrated in the particular case of the spherical wormhole joining with flat exterior space-time. The same conditions, which define the wormhole joining with the exterior space-time, provide the absence of paradoxes in the models with causality violation. It is pointed out, that the nature and physical interpretation of the conditions of wormhole joining with the exterior space-time and induced boundary conditions for the field variables is one of the fundamental problems, which arise in the models with causality violation.

gr-qc↗
arXiv1997

Causality in Topologically Nontrivial Space-Times

The problems causality and causality violation in topologically nontrivial space-time models are considered. To this end the mixed boundary problem for traversable wormhole models is formulated and the influence of the boundary conditions on the causal properties of space-time is analyzed

gr-qc↗
arXiv1997

Comments on the Hypothesis about Possible Class of Particles Able to Travel Faster then Light: Some Geometrical Models

The hypothesis about possible existence of new class of particles able to travel faster then light as a source of dark matter, recently formulated by L. Gonzalez-Mesters, is analyzed. To this end the general geometrical model for several kinds of matter with different Lorentziann structures coexisting on the same manifold is introduced and the local energy density in cosmological reference frame is calculated in two particular cases. It is shown that the local energy density is positive in both considered cases and hence such models really may describe cosmological dark matter. Nevertheless, some problems may appear during the construction of the cosmological models or the models of the compact objects. Moreover, the simplest generalization of the model lead to some variants of vector-tensor theory of gravitation with preferable reference frame which contradict to observations.

physics.gen-ph↗
arXiv1995

Comments on ''The Principle of Self-Consistency as a consequence of the Principle of Minimal Action''

The so called ''Principle of the self-consistency'' for space-time models with causality violation, which was firstly formulated by I.D.Novikov, is discussed for the test particle motion and for test scalar field. It is shown that the constraints, which provide the self-concistensy of test particle motion have pure geometrical (topological) nature. So, the recent statement that ''The Principle of self-consistensy is a consiquence of the Principle of minimal action'' is wrong.

gr-qc↗
arXiv1995

Some Problems of Topology Change Description in the Theory of Space-Time

The problem of topology change description in gravitation theory is analized in detailes. It is pointed out that in standard four-dimensional theories the topology of space may be considered as a particular case of boundary conditions (or constraints). Therefore, the possible changes of space topology in (3+1)-dimensions do not admit dynamical description nor in classical nor in quantum theories and the statements about dynamical supressing of topology change have no sence. In the framework of multidimensional theories the space (and space-time) may be considered as the embedded manifolds. It give the real posibilities for the dynamical description of the topology of space or space-time.

gr-qc↗
arXiv1994

Causality Properties of Topologically Nontrivial Space-Time Models

The causality properties of space-time models with traversable wormholes are considered. It is shown that relativity principle cannot be applied to the motion of the wormhole's mouths in the outer space and the dynamical wormhole transformation into the time machine is impossible. The examples of both causal and noncausal space-time models with traversable wormholes are also considered. Some properties of space-time models with causality violation are briefly discussed.

gr-qc↗
arXiv1994

On Possible Measurement of Gravitational Interaction Parameters on Board a Satellite

The recently suggested SEE (Satellite Energy Exchange) method of measuring the gravitational constant $G$, possible equivalence principle violation (measured by the Eötvös parameter $η$) and the hypothetic 5th force parameters $α$ and $λ$ on board a drag-free Earth's satellite is discussed and further developed. Various particle trajectories near a heavy ball are numerically simulated. Some basic sources of error are analysed. The $G$ measurement procedure is modelled by noise insertion to a ``true'' trajectory. It is concluded that the present knowledge of $G, α$ (for $λ\geq 1$ m) and $η$ can be improved by at least two orders of magnitude.

gr-qc↗