Braz. J. Phys. vol.35 número4B

However if the system is in the region of parametric resonance, initial conditions near the invariant plane would undergo a long time diffusion to large regions of phase space,

We present some cosmological solutions of Brans-Dicke theory, characterized by a decaying vacuum energy density and by a constant relative matter density.. With these features,

Our purpose in this work is to generalize previous results [1–4] and to study static and charged cosmic strings as par- ticular solutions of a Einstein-Maxwell-Dilaton theory of

To get this result we will use the fact that, in the weak field approximation, solutions of scalar- tensor theories are simply related to the solutions of gen- eral relativity

To investigate the extent to which a possible detection of a nontrival topology may place constraints on the cosmological density parameters, we consider here the globally homoge-

Therefore, according to the this theorem, it is possible, to locally embed G¨odel’s solution in a five-dimensional Ricci-flat pseudo-Riemannian space.. From the standpoint of

If the universe is marginally open today, our mechanism allows for a simple, viable and rather efficient amplification of large-scale primordial magnetic fields to strengths that

Some au- thors argued quite convincingly that the large scale distribu- tion of matter should be fractal, quite the oposite to that ex- pected by the cosmological principle..