1,912 research outputs found
Quantum gravitational optics in the field of a gravitomagnetic monopole
Vacuum polarization in QED in a background gravitational field induces
interactions which {\it effectively} modify the classical picture of light rays
as the null geodesics of spacetime. After a short introduction on the main
aspects of the quantum gravitational optics, as a nontrivial example, we study
this effect in the background of NUT space characterizing the spacetime of a
spherical mass endowed with a gravitomagnetic monopole charge, the so called
NUT factor.Comment: 9 pages, title changed and the text abridged for publication in the
Journal of Physics: Conference serie
Gauged motion in general relativity and in Kaluza-Klein theories
In a recent paper [1] a new generalization of the Killing motion, the {\it
gauged motion}, has been introduced for stationary spacetimes where it was
shown that the physical symmetries of such spacetimes are well described
through this new symmetry. In this article after a more detailed study in the
stationary case we present the definition of gauged motion for general
spacetimes. The definition is based on the gauged Lie derivative induced by a
threading family of observers and the relevant reparametrization invariance. We
also extend the gauged motion to the case of Kaluza-Klein theories.Comment: 42 pages, revised version, typos correction along with some minor
changes, Revtex forma
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