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  • 1
    Publication Date: 2014-02-26
    Description: It is well known that the following class of systems of evolution equations \begin{eqnarray} \label{nsgen} \cases{ u_{t}=u_{xx}+F(u,v,u_x,v_x),\cr v_{t}=-v_{xx}+G(u,v,u_x,v_x),\cr} \end{eqnarray} is very rich in integrable cases. The complete classification problem is very difficult. Here we consider only the most interesting (from our opinion) subclass of systems (1). Namely, we consider equations linear in all derivatives of the form \begin{eqnarray} \label{kvazgen} \cases{ u_t = u_{xx} + A_{1}(u,v) u_x + A_{2}(u,v) v_x + A_{0}(u,v)\cr v_t = - v_{xx} + B_{1}(u,v) v_x + B_{2}(u,v) u_x + B_{0}(u,v). \cr} \end{eqnarray} without any restrictions on the functions $A_{i}(u,v), B_{i}(u,v)$.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 2
    Publication Date: 2014-02-26
    Description: We investigate a special class of quadratic Hamiltonians on $so(4)$ and $so(3,1)$ and describe Hamiltonians that have additional polynomial integrals. One of the main results is a new integrable case with an integral of sixth degree.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 3
    Publication Date: 2014-02-26
    Description: Several classes of systems of evolution equations with one or two vector unknowns are considered. We investigate also systems with one vector and one scalar unknown. For these classes all equations having the simplest higher symmetry are listed.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Communications in mathematical physics 193 (1998), S. 245-268 
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract: This paper surveys the classification of integrable evolution equations whose field variables take values in an associative algebra, which includes matrix, Clifford, and group algebra valued systems. A variety of new examples of integrable systems possessing higher order symmetries are presented. Symmetry reductions lead to an associative algebra-valued version of the Painlevé transcendent equations. The basic theory of Hamiltonian structures for associative algebra-valued systems is developed and the biHamiltonian structures for several examples are found.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 197 (1992), S. 87-108 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the bounds of a theoretical scheme treating consistently gravitational interaction as dynamical (gauge) field in flat space-time, an expression was obtained for the density of energy-momentum-tension of gravitational field in vacuum around a collapsed object. A case was studied of an interacting static spherically-symmetric field of a collapsar in vacuum with taking into account of input of all the possible components (spin states of virtual gravitons) into the energy for the symmetric tensor of second rankψ ik . The radius of the sphere filled by matter for the collapsar of massM may achieve values up toGM/c 2.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 197 (1992), S. 179-212 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the bounds of the totally nonmetric model of gravitational interaction theory (gravidynamics) the strong field of a compact object (a collapsar) — an analogue to the black hole in general relativity — is investigated. In the case of utmost strong (for gravidynamics) collapsar, field a region filled, by matter (a bag) must have the radius equal tor *=GM/c 2 ≲10 km at the total collapsar massM≲7M ⊙. Only half of the collapsar mass is contained in the bag, the other one of its total energy (Mc 2 ) is distributed in the space surrounding the bag in the form of ‘a coat’, i.e., in the form of continuous medium (a relativistic ‘gas’) of virtual gravitons. The object must have the surface (the bag surface) with absolutely definite physical properties. The potential of such a surface is finite (ϕ+=-c 2/2) and the particle mass finding itself in a bound state on the bag surface is two times less than the mass of the same particle in a totally free state. The bag surface can perform periodic oscillations (pulsations) with the periodGM/c 2 ≈3×10−5 s. An energy density inside the bag with the utmost strong gravitational field or with an utmost dense ‘coat’ shrouding the bag is determined by gravitation theory constants only and depends on the distance to the bag centerr in the following way: ε(r)=(c 5 /8πG)r −2. The bag matter in the case is most probably in the state of quark-gluon plasma.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 198 (1992), S. 53-70 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From the point of view of a totally nonmetric model of the theory of gravitational interaction, i.e., in the bounds of a consistent dynamic description of gravitation (gravidynamics) a possibility is pointed out of additional loss of energy for the radiation of scalar gravitational waves. Such a radiation arises due to (in particular, periodic) variations, for example, spherically-symmetric pulsations, in a radiating system and is connected with time change of kinetic energy of system. The scalar gravitational ‘luminosity’ in gravidynamics is of the same order (∼G/c 5) as the system energy loss for the radiation of ‘usual’ tensor gravitational waves of general relativity. Perhaps, for a binary system with a nonzero eccentricity it is necessary to account for the influence of scalar radiation on a secular variation of the companion's orbit parameters. The contribution of the scalar radiation into a total gravitational ‘luminosity’ of the system with a radio pulsar PSR 1913+16 can be of the value about 2.2% of the radiation power of the tensor gravitational waves. It can have a considerable effect at measurements of the fall rate of orbital period (P b ) of the binary system, and the corresponding contribution intoP b can be equal to ΔP b ≈−0.053x10−12 ss−1.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 191 (1992), S. 231-258 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the bounds of the consistent dynamic interpretation of gravitation (gravidynamics) a gravitational field has been divided into two components: scalar and tensor, each one interacting with its source by the same coupling constant. Consequently, a spherically-symmetrical gravitational field in vacuum generated by a massive object influences test bodies as an algebraic sum of attraction and repulsion. Field energy in vacuum around the source is also a sum of energies of two components — purely tensor and scalar ones of gravitation. At distances from a gravitating object much greater than its gravitational radius, energies of each separate field component are equal to each other at the same point of space. In the bounds of gravidynamics based on the so-called Einstein's ‘linearized’ equation and proceeding from general principles of theory of classical fields a statement (a theorem) has been formulated on the static gravitational field of a collapsar: a spherically-symmetric object generating a static field in vacuum may always only occupy a finite, nonzero volume.
    Type of Medium: Electronic Resource
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