Scalar fields in an anisotropic closed universe
نویسندگان
چکیده
منابع مشابه
A Matter Scalar Field in a Closed Universe
We investigate the possibility that the matter of the universe has a significant component (the quintessence component) determined by the equation of state p = wρ, with w < 0. Here, we find conditions under which a closed model may look like a flat Friedmann-Robertson-Walker universe at low redshift. We study this problem in Einstein’s general relativity and Brans-Dicke theories. In both cases ...
متن کاملScalar - tensor gravity in an accelerating universe
We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of the Lagrangian, and we stress that apparent singularities are sometimes artifacts of a pathological choice of variables. Adopting a phenomenological viewpoint, i.e., from the observations back to the t...
متن کاملNoether Symmetry in f(T) Theory at the anisotropic universe
As it is well known, symmetry plays a crucial role in the theoretical physics. On other hand, the Noether symmetry is a useful procedure to select models motivated at a fundamental level, and to discover the exact solution to the given lagrangian. In this work, Noether symmetry in f(T) theory on a spatially homogeneous and anisotropic Bianchi type I universe is considered. We discuss the Lagran...
متن کاملDiscrete spectral shift in an anisotropic universe
In this paper we calculate the particle creation as seen by a stationary observer in an anisotropic universe. By using an observer and geometry dependent time to quantise a massive scalar field we show that a discrete energy spectrum shift occurs. The length scale associated with the geometry provides the energy scale by which the spectrum is shifted. The β(p, q) coefficient for the Bogolubov t...
متن کاملWaves and instabilities in an anisotropic universe
The excitation of low frequency plasma waves in an expanding anisotropic cosmological model that contains a magnetic field frozen into the matter and pointing in the longitudinal direction is discussed. Using the exact equations governing finite-amplitude wave propagation in hydromagnetic media within the framework of the general theory of relativity, we show that a spectrum of magnetized sound...
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: 2000
ISSN: 0556-2821,1089-4918
DOI: 10.1103/physrevd.62.023501