Warm inflation with back - reaction: a stochastic approach

I study a stochastic approach for warm inflation considering back - reaction of the metric with the fluctuations of matter field. This formalism takes into account the local inhomogeneities fo the spacetime in a globally flat Friedmann - Robertson - Walker metric. The stochastic equations for the fluctuations of the matter field and the metric are obtained. Finally, the dynamics for the amplitude of these fluctuations in a power - law expansion for the universe are examined.Comment: minor changes, 6 pages, no figures, accepted for publication in Classical and Quantum Gravit

Towards a theory of Warm Inflation of the Universe

The warm inflation scenario is an alternative mechanism which can explain the isotropic and homogeneous Universe which we are living in. In this work I extend a previously introduced formalism, without the restriction of slow - roll regime. Quantum to classical transition of the fluctuations is studied by means of the "transition function" here introduced. I found that the fluctuations of radiation energy density decrease with time and the thermal equilibrium at the end of inflation holds.Comment: 14 pages, no figures, to appear in Classical and Quantum Gravit

Gravitational confinement of photons and matter from Induced Matter theory

Using an Extended Scharzschild-Anti de Sitter (ESAdS) metric here introduced, where the noncompact extra dimension is time-like, we study the gravitational confinement of matter and photons from a 5D vacuum. The important result here obtained is that the photon trajectories (in general, massless particles) are periodic. They are confined to a radius $r\leq 2 m G/c^2$ by the gravitational field. Massive test particles are also gravitationally confined, but their trajectories are not periodic.Comment: Version to be published in "Results in Physics". arXiv admin note: text overlap with arXiv:0802.093