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Pawel Gusin

Publications and source records attributed to Pawel Gusin.

10 recordsLinked to original sources
arXiv2023

Quantum phenomena inside a black hole: quantization of the scalar field iniside horizon in Schwarzschild spacetime

We discuss the problem of the quantization and dynamic evolution of a scalar free field in the interior of a Schwarzschild black hole. A unitary approach to the dynamics of the quantized field is proposed: a time-dependent Hamiltonian governing the Heisenberg equations is derived. It is found that the system is represented by a set of harmonic oscillators coupled via terms corresponding to the creation and annihilation of pairs of particles and that the symmetry properties of the spacetime, homogeneity and isotropy are obeyed by the coupling terms in the Hamiltonian. It is shown that Heisenberg equations for annihilation and creation operators are transformed into ordinary differential equations for appropriate Bogolyubov coefficients. Such a formulation leads to a general question concerning the possibility of gravitationally driven instability, that is however excluded in this case.

gr-qc↗
arXiv2017

The volume of the black holes - the constant curvature slicing of the spherically symmetric spacetime

We consider the problem of determination of a volume of some bounded space-like hypersurfaces in the case of spherically symmetric spacetimes. In the case when the hypersurfaces is cut or bounded by a light-like hypersurface the problem may not be well defined. In order to define properly the volume we introduce the volume forms related to the given foliation (observer) of the considered spacetime. In the case of the constant curvature slice the volume of the hypersurface cut by the horizon (light-like surface) becomes composed of the two parts, outer and inner, treated differently. We compute the corresponding volumes outside and inside of the horizon of the ethernal Schwarzschild black hole.

gr-qc↗
arXiv2016

D2 brane as the wormhole and the number of the universes

We construct wormhole-like solutions in the type IIA string theory. These solutions represent wormholes in four-dimensions and are given by the D2 branes within appropraited backgrounds fields. We present the conditions on these fields which lead to the four-dimensional wormholes. In the special case we show how the particular solution in the type IIA theory leads to the dynamic wormhole. We also speculate about the number of universes and the cosmological constant.

hep-th↗
arXiv2015

Observers in spacetimes with spherical and axial symmetries

We introduce in the explicit form the tetrads of arbitrary observers in spacetimes with spherical and axial symmetries. The observers confined to the equatorial plane are parametrized by the pair of functions. We apply this description in the analysis of the null-geodesics in the observers' frames. The observers with the constant acceleration are distinguished.

gr-qc↗
arXiv2009

Anisotropic evolution of a D-brane

The evolution of a probe D-brane in the p-brane background has been considered. The anisotropic evolution of the world-volume of the D-brane with a given topology of a world-volume in a form of a direct product of a n-dimensional flat space and (3-n)-dimensional sphere has been obtained. In this case the anisotropy is described with the aid of two parameters (Hubble parameters). The special case of this evolution, namely the isotropic evolution corresponds to equality of these two parameters. In the latter case the masses and charges of the background p-branes have been derived.

hep-th↗
arXiv2008

The Hubble parameters in the D-brane models

We consider the DBI action for the D-branes with the dynamic embeddings in the background produced by p-branes. For the D-brane with the special topology we obtain two Hublle parameters on this brane. The condition for the equality of these parameters is analyzed. In the special case a mass and a charge of the background p-branes are derived from this condition.

hep-th↗
arXiv2008

Inflation conditions for non-BPS D-branes

We investigate the effective action for a non-BPS brane in a time-depending embedding. This action is considered as the action for tachyon and embedding coupled to the brane gravity. We derive the slow roll parameters from this model.

hep-th↗
arXiv2008

Wheeler-De Witt equation for brane gravity

We consider the gravity in the system consisting of the Bogomol'nyi-Prasad-Sommerfield (BPS) D3-brane embedded in the flat background geometry, produced by the solutions of the supergravity. The effective action for this system is represented by the sum of the Hilbert-Einstein and DBI actions. We derive the Wheeler-De Witt equation for this system and obtain analytical solutions in some special cases. We also calculate tunneling probability from Planckian size of D3-brane to the classical regime.

hep-th↗
arXiv2008

Evolution of the D3-brane for dynamical embeddings

The Dirac-Born-Infeld (DBI) action of the 3-dimensional brane for its dynamical embeddings and the gauge fields has been studied. The evolution of both the D3-brane and the ambient space has been obtained. For the special constraint put on the transverse coordinates a family of the contracting and expanding spaces has been found.

hep-th↗