The characteristic initial-value problem of the gravitational and N-Maxwell plane wave collision is solved exactly.


Neutrino oscillations induced by spacetime torsion
Adak, M; Dereli, T; Ryder, LH (IOP Publishing, 2001-04-21)
The gravitational neutrino oscillation problem is studied by considering the Dirac Hamiltonian in a Riemann-Cartan spacetime and calculating the dynamical phase. Torsion contributions which depend on the spin direction of the mass eigenstates are found. These effects are of the order of Planck scales.
Exact formulas for spherical photon orbits around Kerr black holes
Tavlayan, Aydın; Tekin, Bayram (American Physical Society (APS), 2020-11-01)
Exact formulas relating the radii of the spherical photon orbits to the black hole's rotation parameter and the effective inclination angle of the orbit have been known only for equatorial and polar orbits up to now. Here we provide exact formulas for nonequatorial orbits that lie between these extreme limits. For a given rotation parameter of the black hole, there is a critical inclination angle below which there are four null photon orbits two of which are in the exterior region. At the critical angle, th...
Event horizon detecting invariants
Tavlayan, Aydın; Tekin, Bayram (American Physical Society (APS), 2020-04-14)
Some judiciously chosen local curvature scalars can be used to invariantly characterize event horizons of black holes inD > 3 dimensions, but they fail for the three dimensional Banados-Teitelboim-Zanelli (BTZ) black hole since all curvature invariants are constant. Here we provide an invariant characterization of the event horizon of the BTZ black hole using the curvature invariants of codimension one hypersurfaces instead of the full spacetime. Our method is also applicable to black holes in generic dimen...
Shortcuts to spherically symmetric solutions: a cautionary note
Deser, S; Franklin, J; Tekin, Bayram (IOP Publishing, 2004-11-21)
Spherically symmetric solutions of generic gravitational models are optimally, and legitimately, obtained by expressing the action in terms of the surviving metric components. This shortcut is not to be overdone; however, a one-function ansatz invalidates it, as illustrated by the incorrect solutions of Wohlfarth (2004 Class. Quantum Grav. 21 1927).
Spherically symmetric solutions of Einstein plus non-polynomial gravities
Deser, S.; Sarıoğlu, Bahtiyar Özgür; Tekin, Bayram (Springer Science and Business Media LLC, 2008-01-01)
We obtain the static spherically symmetric solutions of a class of gravitational models whose additions to the General Relativity (GR) action forbid Ricci-flat, in particular, Schwarzschild geometries. These theories are selected to maintain the (first) derivative order of the Einstein equations in Schwarzschild gauge. Generically, the solutions exhibit both horizons and a singularity at the origin, except for one model that forbids spherical symmetry altogether. Extensions to arbitrary dimension with a cos...
Citation Formats
M. GURSES and E. A. Karasu, “COLLIDING ABELIAN GAUGE PLANE-WAVES,” CLASSICAL AND QUANTUM GRAVITY, pp. 0–0, 1989, Accessed: 00, 2020. [Online]. Available: