Massless fields in scalar-tensor cosmologies
نویسندگان
چکیده
منابع مشابه
Massless fields in scalar-tensor cosmologies.
We derive exact Friedmann–Robertson–Walker cosmological solutions in general scalar–tensor gravity theories, including Brans–Dicke gravity, for stiff matter or radiation. These correspond to the long or short wavelength modes respectively of massless scalar fields. If present, the long wavelength modes of such fields would be expected to dominate the energy density of the universe at early time...
متن کاملAnisotropic scalar-tensor cosmologies.
We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state (p ∝ ρ) in a spatially flat (Bianchi type I) cosmology. These models approach an isotropic, general relativistic solution as the expansion becomes dominated by the barot...
متن کاملSingularities In Scalar-Tensor Cosmologies
In this article, we examine the possibility that there exist special scalar-tensor theories of gravity with completely nonsingular FRW solutions. Our investigation in fact shows that while most probes living in such a Universe never see the singularity, gravity waves always do. This is because they couple to both the metric and the scalar field, in a way which effectively forces them to move al...
متن کاملScaling solutions in scalar-tensor cosmologies
The possibility of a connection between dark energy and gravity through a direct coupling in the Lagrangian of the underlying theory has acquired an increasing interest due to the recently discovered capability of the extended quintessence model to encompass the fine-tuning problem of the cosmological constant. The gravity induced “R-boost” mechanism is indeed responsible for an early, enhanced...
متن کامل0 Double Scalar – Tensor Gravity Cosmologies
We investigate homogeneous and isotropic cosmological models in scalar–tensor theories of gravity where two scalar fields are nonminimally coupled to the geometry. Exact solutions are found, by Noether symmetries, depending on the form of couplings and self–interaction potentials. An interesting feature is that we deal with the Brans–Dicke field and the inflaton on the same ground since both ar...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physical Review D
سال: 1995
ISSN: 0556-2821
DOI: 10.1103/physrevd.51.477