69 research outputs found
On Rumer’s Invariant Theory of Gravitational Waves
Propagation of gravitational potential and gravitational field-strength has been considered here on the basis of Rumer’s Invariant Theory of Gravitational Waves. Finally some special cases of weak field have been discusse
Quasinormal modes for the charged Vaidya metric
The scalar wave equation is considered in the background of a charged Vaidya
metric in double null coordinates describing a non-stationary charged
black hole with varying mass and charge . The resulting
time-dependent quasinormal modes are presented and analyzed. We show, in
particular, that it is possible to identify some signatures in the quasinormal
frequencies from the creation of a naked singularity.Comment: 4 pages. Prepared for the proceedings of the Spanish Relativity
meeting (ERE2010), Granada, Spain, September 6-10, 201
The Birkhoff Theorem in Multidimensional Gravity
The validity conditions for the extended Birkhoff theorem in multidimensional
gravity with internal spaces are formulated, with no restriction on
space-time dimensionality and signature. Examples of matter sources and
geometries for which the theorem is valid are given. Further generalization of
the theorem is discussed.Comment: 8 page
A Class of Renormalization Group Invariant Scalar Field Cosmologies
We present a class of scalar field cosmologies with a dynamically evolving
Newton parameter and cosmological term . In particular, we discuss
a class of solutions which are consistent with a renormalization group scaling
for and near a fixed point. Moreover, we propose a modified
action for gravity which includes the effective running of and
near the fixed point. A proper understanding of the associated variational
problem is obtained upon considering the four-dimensional gradient of the
Newton parameter.Comment: 10 pages, RevTex4, no figures, to appear on GR
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