arXiv subjects

I. Sakalli

Publications and source records attributed to I. Sakalli.

43 records · Page 3Linked to original sources

arXiv2008

Hawking radiation for higher dimensional Einstein-Yang-Mills linear dilaton black holes

Recently, Hawking radiation from a $4-$dimensional linear dilaton black hole solution to Einstein-Maxwell-Dilaton (EMD) theory, via a method of computing exactly the semi-classical radiation, has been derived by Cl\U{e9}ment, et al. Their results show that, whenever solution is available to the massless scalar wave equation, an exact computation of the radiation spectrum leads to the Hawking temperature $T_{H}$. We apply the same method to derive Hawking radiation spectrum for higher dimensional linear dilaton black holes in the Einstein-Yang-Mills-Dilaton (EYMD) and Einstein-Maxwell-Dilaton (EMD) theories. Our results show that the radiation with high frequencies for these massive black holes reveal some remarkable information about the $T_{H}$.

gr-qc↗

arXiv2008

Solution of the Dirac equation in the rotating Bertotti-Robinson spacetime

The Dirac equation is solved in the rotating Bertotti-Robinson spacetime. The set of equations representing the Dirac equation in the Newman-Penrose formalism is decoupled into an axial and angular part. The axial equation, which is independent of mass, is solved exactly in terms of hypergeometric functions. The angular equation is considered both for massless (neutrino) and massive spin-(1/2) particles. For the neutrinos, it is shown that the angular equation admits an exact solution in terms of the confluent Heun equation. In the existence of mass, the angular equation does not allow an analytical solution, however, it is expressible as a set of first order differential equations apt for numerical study.

gr-qc↗

arXiv2007

Chaos in Kundt type III Spacetimes

We consider geodesics motion in a particular Kundt type III spacetime in which Einstein-Yang-Mills equations admit solutions. On a particular surface as constraint we project the geodesics into the (x,y) plane and treat the problem as a 2-dimensional one. Our numerical study shows that chaotic behavior emerges under reasonable conditions.

gr-qc↗

arXiv2004

Solution of Dirac equation in the near horizon geometry of an extreme Kerr black hole

Dirac equation is solved in the near horizon limit geometry of an extreme Kerr black hole. We decouple equations first as usual, into an axial and angular part. The axial equation turns out to be independent of the mass and is solved exactly. The angular equation reduces, in the massless case, to a confluent Heun equation. In general for nonzero mass, the angular equation is expressible at best, as a set of coupled first order differential equations apt for numerical investigation. The axial potentials corresponding to the associated Schrodinger-type equations and their conserved currents are found. Finally, based on our solution, we verify in a similar way the absence of superradiance for Dirac particles in the near horizon, a result which is well-known within the context of general Kerr background.

gr-qc↗

arXiv2003

New Singular and Nonsingular Colliding Wave Solutions in Einstein - Maxwell - Scalar Theory

A technique is given to generate coupled scalar field solutions in colliding Einstein - Maxwell (EM) waves. By employing the Bell - Szekeres solution as seed and depending on the chosen scalar field it is possible to construct nonsingular solutions. If the original EM solution is already singular addition of scalar fields does not make the physics any better. In particular, scalar field solution that is transformable to spherical symmetry is plagued with singularities.

gr-qc↗

arXiv2003

Collision of Electromagnetic Shock Waves Coupled with Axion Waves: An Example

We present an exact solution that describes collision of electromagnetic shock waves coupled with axion plane waves. The axion has a rather special coupling to the cross polarization term of the metric. The initial data on the null surfaces is well-defined and collision results in a singularity free interaction region. Our solution is a generalization of the Bell-Szekeres solution in the presence of an axion field.

gr-qc↗

arXiv2003

Scalar Field Solutions in Colliding Einstein-Maxwell Waves

A simple method is presented which enables us to construct scalar field solutions from any given Einstein-Maxwell solution in colliding plane waves. As an application we give scalar field extensions of the solution found by Hogan, Barrabes and Bressange.

gr-qc↗