6 papers
Superinflation, quintessence, and the avoidance of the initial singularity
A. Saa, E. Gunzig, L. Brenig +3
We consider the dynamics of a spatially flat universe dominated by a self-interacting nonminimally coupled scalar field. The structure of the phase space and complete phase portrai…
Einstein frame or Jordan frame ?
Valerio Faraoni, Edgard Gunzig
Scalar-tensor theories of gravity can be formulated in the Jordan or in the Einstein frame, which are conformally related. The issue of which conformal frame is physical is a conte…
Does the non-minimal coupling of the scalar field improve or destroy inflation ?
Valerio Faraoni
The non-minimal coupling of a scalar field to the Ricci curvature in a curved spacetime is unavoidable according to several authors. The coupling constant is not a free parameter:…
Light amplification by gravitational waves in scalar-tensor theories of gravity
Valerio Faraoni
It is shown that the amplification of a light beam by gravitational waves in scalar-tensor theories of gravity is a first order effect in the wave amplitudes. In general relativity…
Experimental limits on antigravity in extended supergravity
S. Bellucci, V. Faraoni
The available tests of the equivalence principle constrain the mass of the Higgs-like boson appearing in extended supergravity theories. We determine the constraints imposed by the…
On the rotation of polarization by a gravitational lens
Valerio Faraoni
It is proved that the field of a gravitational lens induces no rotation in the polarization vector of electromagnetic radiation, in agreement with the previous literature, but with…