Closed timelike curves and geodesics of Godel-type metrics

it is shown explicitly that when the characteristic vector field that defines a Godel-type metric is also a Killing vector, there always exist closed timelike or null curves in spacetimes described by such a metric. For these geometries, the geodesic curves are also shown to be characterized by a lower-dimensional Lorentz force equation for a charged point particle in the relevant Riemannian background. Moreover, two explicit examples are given for which timelike and null geodesics can never be closed.


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).
Massive, topologically massive, models
Deser, S; Tekin, Bayram (IOP Publishing, 2002-06-07)
In three dimensions, there are two distinct mass-generating mechanisms for gauge fields: adding the usual Proca/Pauli-Fierz, or the more esoteric Chern-Simons (CS), terms. Here, we analyse the three-term models where both types are present and their-various limits. Surprisingly, in the tensor case, these seemingly innocuous systems are physically unacceptable. If the sign of the Einstein term is 'wrong', as is in fact required in the CS theory, then the excitation masses are always complex; with the usual s...
Kerr-Schild-Kundt metrics are universal
GÜRSES, METİN; Sisman, Tahsin Cagri; Tekin, Bayram (IOP Publishing, 2017-04-06)
We define (non-Einsteinian) universal metrics as the metrics that solve the source-free covariant field equations of generic gravity theories. Here, extending the rather scarce family of universal metrics known in the literature, we show that the Kerr-Schild-Kundt class of metrics are universal. Besides being interesting on their own, these metrics can provide consistent backgrounds for quantum field theory at extremely high energies.
DERELI, T; MUKHERJEE, M; TUCKER, RW (IOP Publishing, 1988-01-01)
A set of symmetric, traceless, divergence-free differential forms, Weyl covariant under a conformal scaling of a (pseudo-)Riemannian metric, is constructed in 4n-1 dimensions.
Dark matter as a localized scalar in the extra dimension
Iltan, E. O. (Springer Science and Business Media LLC, 2009-12-01)
We consider a standard model singlet which is accessible to a single extra dimension and its zero mode is localized with Gaussian profile around a point different from the origin. This zero-mode scalar is a possible candidate for the dark matter and its annihilation rate is sensitive to the compactification radius of the extra dimension, the localization width and the position. For the case of non-resonant annihilation, we estimated the dark matter scalar location around a point, at a distance similar to 3x...
Citation Formats
R. Gleiser, M. Gurses, A. Karasu, and B. Ö. Sarıoğlu, “Closed timelike curves and geodesics of Godel-type metrics,” CLASSICAL AND QUANTUM GRAVITY, pp. 2653–2663, 2006, Accessed: 00, 2020. [Online]. Available: