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V. I. Tkach

Publications and source records attributed to V. I. Tkach.

At least 19 recordsLinked to original sources

Towards Ghost-Free Gravity and Standard Model

This paper presents a new higher derivative gravity which in spontaneous breaking electroweak symmetry state does not have ghost in gravity sector. We show that Newton constant of the gravity and dark energy density they depend on the fundamental TeV scale and the coupling constant at the quadratic curvature term. We consider the supersymmetric extension of this model.

hep-th

Fractional Electromagnetic Waves

In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <γ<1. A new parameter σ, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for γ= 1 and γ= 1/2 cases.

math-ph

Supersymmetric Cosmological FRW Model and Dark Energy

In this work we consider a flat cosmological model with a set of fluids in the framework of supersymmetric cosmology. The obtained supersymmetric algebra allowed us to take quantum solutions. It is shown that only in the case of a cosmological constant we have a condition between the density of dark energy $ρ_Λ$ and density energy of matter $ρ_M$, $ρ_Λ> 2ρ_M$.

gr-qc

Supersymmetric Barotropic FRW Model and Dark Energy

Using the superfield approach we construct the $n=2$ supersymmetric lagrangian for the FRW Universe with barotropic perfect fluid as matter field. The obtained supersymmetric algebra allowed us to take the square root of the Wheeler-DeWitt equation and solve the corresponding quantum constraint. This model leads to the relation between the vacuum energy density and the energy density of the dust matter.

gr-qc

Supersymmetric Cosmology and Dark Energy

Using the superfield approach we construct the n = 2 supersymmetric lagrangian for the FRW Universe with perfect fluid as matter fields. The obtained supersymmetric algebra allowed us to take the square root of the Wheeler-DeWitt equation and solve the corresponding quantum constraint. This model leads to the relation between the vacuum energy density and the energy density of the dust matter.

gr-qc

FRW cosmological model inside an isolated Schwarzschild black hole

Using the canonical quantum theory of spherically symmetric pure gravitational systems, we present a direct correspondence between the Friedmann-Robertson-Walker (FRW) cosmological model in the interior of a Schwarzschild black hole and the nth energy eigenstate of a linear harmonic oscillator. Such type of universe has a quantized mass of the order of the Planck mass and harmonic oscillator wave functions

gr-qc

Inflation from Susy quantum cosmology

We propose a realization of inverted hybrid inflation scenario in the context of n=2 supersymmetric quantum cosmology. The spectrum of density fluctuations is calculated in the de Sitter regimen as a function of the gravitino and the Planck mass, and explicit forms for the wave function of the universe are found in the WKB regimen for a FRW closed and flat universes.

hep-th

Extended supersymmetry for the Bianchi-type cosmological models

In this paper we propose a superfield description for all Bianchi-type cosmological models. The action is invariant under world-line local $n=4$ supersymmetry with $SU(2)_{local}XSU(2)_{global}$ internal symmetry. Due to the invariance of the action we obtain the constraints, which form a closed superalgebra of the $n=4$ supersymmetric quantum mechanics. This procedure provides the inclusion of supermatter in a sistematic way.

hep-th

Susy Cosmological Models

In this work we consider the action for a set of complex scalar supermultiplets interacting with the scale factor in the supersymmetric cosmological models. We show that the local conformal supersymmetry leads to a scalar field potential defined in terms of the Kähler potential and superpotential. Using supersymmetry breaking we are able to obtain a normalizable wave function for the FRW cosmological model.

hep-th

On the n=4 Supersymmetry for the FRW Model

In this work we have constructed the n=4 extended local conformal time supersymmetry for the Friedmann-Robertson-Walker (FRW) cosmological models. This is based on the superfield construction of the action, which is invariant under wordline local n=4 supersymmetry with $SU(2)_{local} \otimes SU(2)_{global}$ internal symmetry. It is shown that the supersymmetric action has the form of the localized (or superconformal) version of the action for n=4 supersymmetric quantum mechanics. This superfield procedure provides a well defined scheme for including supermatter.

hep-th

On the Schrödinger Equation for the Supersymmetric FRW Model

We consider a time-dependent Schrödinger equation for the Friedmann-Robertson-Walker (FRW) model. We show that for this purpose it is possible to include an additional action invariant under reparametrization of time. The last one does not change the equations of motion for the minisuperspace model, but changes only the constraint. The same procedure is applied to the supersymmetric case.

hep-th

Entropy using Path Integrals for Quantum Black Hole Models

Several eigenvalue equations that could describe quantum black holes have been proposed in the canonical quantum gravity approach. In this paper, we choose one of the simplest of these quantum equations to show how the usual Feynman's path integral method can be applied to obtain the corresponding statistical properties. We get a logarithmic correction to the Bekenstein-Hawking entropy as already obtained by other authors by other means.

gr-qc

On the Schrodinger Equation for the Minisuperspace Models

We obtain a time-dependent Schrodinger equation for the Friedmann - Robertson - Walker (FRW) model interacting with a homogeneous scalar matter field. We show that for this purpose it is necesary to include an additional action invariant under the reparametrization of time. The last one does not change the equations of motion of the system, but changes only the constraint which at the quantum level becomes time-dependent Schrodinger equation. The same procedure is applied to the supersymmetric case and the supersymmetric quantum constraints are obtained, one of them is a square root of the Schrodinger operator.

hep-th

Reparametrization Invariance and the Schrödinger Equation

In the present work we consider a time-dependent Schrödinger equation for systems invariant under the reparametrization of time. We develop the two-stage procedure of construction such systems from a given initial ones, which is not invariant under the time reparametrization. One of the first-class constraints of the systems in such description becomes the time-dependent Schrödinger equation. The procedure is applicable in the supersymmetric theories as well. The $n=2$ supersymmetric quantum mechanics is coupled to world-line supergravity, and the local supersymmetric action is constructed leading to the square root representation of the time-dependent Schrödinger equation.

hep-th

The wave function of the universe and spontaneaus breaking of supersymmetry

In this work we define a scalar product ``weighted'' with the scalar factor $R$ and show how to find a normalized wave function for the supersymmetric quantum FRW cosmological model using the idea of supersymmetry breaking selection rules under local n=2 conformal supersymmetry. We also calculate the expectation value of the scalar factor R in this model and its corresponding behaviour.

hep-th

On the relation of the gravitino mass and the GUT parameters

In this article we consider the local supersymmetry breaking and the broken SU(5) symmetry permisible by dilaton vacuum configuration in supergravity theories. We establish the parameter relation of spontaneuos breaking of supersymmetry and of the GUT theory.

hep-th