ar X iv : g r - qc / 9 51 20 07 v 1 2 9 N ov 1 99 5 Consequences of the noncompactness of the Lorentz
نویسنده
چکیده
The following four statements have been proven decades ago already, but they continue to induce a strange feeling: All curvature invariants of a gravitational wave vanish inspite of the fact that it represents a nonflat spacetime. The eigennullframe components of the curvature tensor (the Cartan ”scalars”) do not represent curvature scalars. The Euclidean topology in the Minkowski spacetime does not possess a basis composed of Lorentz–invariant neighbourhoods. There are points in the de Sitter spacetime which cannot be joined to each other by any geodesic. We explain that our feeling is influenced by the compactness of the rotation group; the strangeness disappears if we fully acknowledge the noncompactness of the Lorentz group. Output: Imaginary coordinate rotations from Euclidean to Lorentzian signature are very dangerous. AMS number: 53 B 30 Lorentz metrics, indefinite metrics PACS number: 0430 Gravitational waves: theory
منابع مشابه
ar X iv : g r - qc / 9 51 10 48 v 1 1 6 N ov 1 99 5 Two lectures on Two - Dimensional Gravity ∗
متن کامل
ar X iv : g r - qc / 9 51 10 66 v 1 2 4 N ov 1 99 5 Scalar Field Inhomogeneous
Some exact solutions for the Einstein field equations corresponding to inhomogeneous G 2 cosmologies with an exponential-potential scalar field which generalize solutions obtained previously are considered. Several particular cases are studied and the properties related to generalized inflation and asymptotic behaviour of the models are discussed.
متن کاملar X iv : g r - qc / 0 51 11 52 v 1 2 9 N ov 2 00 5 Recent results on the search for continuous sources with LIGO and GEO 600 Alicia
An overview of the searches for continuous gravitational wave signals in LIGO and GEO 600 performed on different recent science runs and results are presented. This includes both searching for gravitational waves from known pulsars as well as blind searches over a wide parameter space.
متن کاملar X iv : g r - qc / 9 61 10 11 v 1 5 N ov 1 99 6 On Relation between String Theory and Multidimensional Cosmology
It is shown that a transition from a multidimensional cosmological model with one internal space of the dimension d 1 to the effective tree-level bosonic string corresponds to an infinite number of the internal dimensions: d 1 → ∞.
متن کاملar X iv : g r - qc / 9 81 10 89 v 1 2 6 N ov 1 99 8 Spectral methods in general relativistic astrophysics
We present spectral methods developed in our group to solve three-dimensional partial differential equations. The emphasis is put on equations arising from astro-physical problems in the framework of general relativity.
متن کامل