Plamen Fiziev

Publications (60) View all

• Article: J. Phys. A: Math. Gen. 29 (1996) 7619--7624. Printed in the UK Comment on path integral derivation of Schr odinger equation in spaces with curvature and torsion

  P. Fiziev, H. Kleinert
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  ABSTRACT: We present a derivation of the Schr odinger equation for a path integral of a point particle in a space with curvature and torsion which is considerably shorter and more elegant than that commonly found in the literature. 1.
  10/2001;
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  Available from: Plamen Fiziev

  Article: Minimal Model of Dilatonic Gravity and Cosmological Constant

  P. Fiziev
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  ABSTRACT: We consider: minimal scalar-tensor model of gravity with Brans-Dicke factor $\omega(\Phi)\equiv 0$ and cosmological factor $\Pi(\Phi)$; restrictions on it from gravitational experiments; qualitative analysis of new approach to cosmological constant problem based on the huge amount of action in Universe; determination of $\Pi(\Phi)$ using time evolution of scale factor of Universe.
  10/2000;
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  Available from: Plamen Fiziev

  Article: Cosmological Constant or Cosmological Potential

  P. Fiziev
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  ABSTRACT: In the framework of a model of minimal of dilatonic gravity (MDG) with cosmological potential we consider: the relations of MDG with nonlinear gravity and string theory; natural cosmological units, defined by cosmological constant; the properties of cosmological factor, derived from solar system and Earth-surface gravitational experiments; universal anty-gravitational interactions, induced by positive cosmological constant and by Nordtved effect; a new formulation of cosmological constant problem using the ratio of introduced cosmological action and Planck constant $\sim 10 ^{122}$;qualitative analysis of this huge number based on classical action of effective Bohr hydrogen atoms; inverse cosmological problem: to find cosmological potential which yields given evolution of the RW Universe; and comment other general properties of MDG.
  09/2000;
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  Available from: Plamen Fiziev

  Article: New Numerical Algorithm for Modeling of Boson-Fermion Stars in Dilatonic Gravity

  T. L. Boyadjiev, M. D. Todorov, P. P. Fiziev, S. S. Yazadjiev
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  ABSTRACT: We investigate numerically a models of the static spherically symmetric boson-fermion stars in scalar-tensor theory of gravity with massive dilaton field. The proper mathematical model of such stars is interpreted as a nonlinear two-parametric eigenvalue problem with unknown internal boundary. We employ the Continuous Analogue of Newton Method (CANM) which leads on each iteration to two separate linear boundary value problems with different dimensions inside and outside the star, respectively. Along with them a nonlinear algebraic system for the spectral parameters - radius of the star $R_{s}$ and quantity $\Omega $ is solved also. In this way we obtain the behaviour of the basic geometric quantities and functions describing dilaton field and matter fields which build the star.
  05/2000;
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  Article: Boson stars in massive dilatonic gravity

  P. Fiziev, S. Yazadjiev, T. Boyadjiev, M. Todorov
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  ABSTRACT: We study equilibrium configurations of boson stars in the framework of a class scalar-tensor theories of gravity with massive gravitational scalar (dilaton). In particular we investigate the influence of the mass of the dilaton on the boson star structure. We find that the masses of the boson stars in presence of dilaton are close to those in general relativity and they are sensitive to the ratio of the boson mass to the dilaton mass within a typical few percent. It turns out also that the boson star structure is mainly sensitive to the mass term of the dilaton potential rather to the exact form of the potential. Comment: 9 pages, latex, 9 figures, one figure dropped, new comments added, new references added, typos corrected
  01/2000;