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 ...

Using a generalized coordinate along with a proper invertible coordinate transformation, we show that the Euler–Lagrange equation used by Bagchi et al (2013 J. Phys. A: Math. Theor. 46 032001) is in clear violation of ...

We consider the interesting ‘‘near-horizon test’’ reported in S. E. P. Bergliaffa and Y. E. C. de O. Nunes,Phys. Rev. D 84, 084006 (2011) for any static, spherically symmetric black hole solution admitted in f(R)gravity. ...

A complexified von Roos Hamiltonian is considered and a Hermitian firstorder intertwining differential operator is used to obtain the related positiondependent mass η-weak-pseudo-HermitianHamiltonians. Using a Liouvilleantype ...

We consider the particular class of f(R) gravities minimally coupled with Yang - Mills (YM) field in which the Ricci scalar =R_{0}= constant in all dimensions d\geq4. Even in this restricted class the spacetime has unlimited ...

The speed of light is taken to be a constant in a vacuum. This forms the basic tool for the principle of General Covariance, which asserts that, all laws of Physics should take the same form in all frames of reference. ...

Using Einstein-Rosen's linearly polarized waves as the seed solution, we derive an interesting solution for the Einstein's equations that describes the evolution of such waves with the second polarization.

ABSTRACT: The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I review some candidates of dark matter, especially WIMPs (weakly interacting massive particles) ...

Thin-shell wormholes in Einstein-Yang-Mills-dilaton (EYMD) gravity are considered. We show that a non-asymptotically flat (NAF) black hole solution of the d-dimensional EYMD theory provides stable thin-shell wormholes which ...