249 citations
- Université de SherbrookeCA3 papers
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18 papers · 1 filter
Scalar field mass in generalized gravity
Valerio Faraoni
The notions of mass and range of a Brans-Dicke-like scalar field in scalar-tensor and f(R) gravity are subject to an ambiguity that hides a potential trap. We spell out this ambigu…
Averaging inhomogeneities in scalar-tensor cosmology
Vincenzo Vitagliano, Stefano Liberati, Valerio Faraoni
The backreaction of inhomogeneities on the cosmic dynamics is studied in the context of scalar-tensor gravity. Due to terms of indefinite sign in the non-canonical effective energy…
Gravitationally coupled magnetic monopole and conformal symmetry breaking
Ariel Edery, Luca Fabbri, M. B. Paranjape
We consider a Georgi-Glashow model conformally coupled to gravity. The conformally invariant action includes a triplet of scalar fields and SO(3) non-Abelian gauge fields. However,…
Position and frequency shifts induced by massive modes of the gravitational wave background in alternative gravity
S. Bellucci, S. Capozziello, M. De Laurentis +1
Alternative theories of gravity predict the presence of massive scalar, vector, and tensor gravitational wave modes in addition to the standard massless spin~2 graviton of general…
What is the fate of a black hole embedded in an expanding universe?
Valerio Faraoni, Changjun Gao, Xuelei Chen +1
Within a large class of exact solutions of the Einstein equations describing a black hole embedded in a Friedmann universe it is shown that, under certain assumptions, only those w…
Extension of the EGS theorem to metric and Palatini f(R) gravity
Valerio Faraoni
By using the equivalence between metric and Palatini f(R) (or "modified") gravities with omega=0, -3/2 Brans-Dicke theories, it is shown that the Ehlers-Geren-Sachs theorem of gene…