Non-singular pre-big bang scenarios from all-order α′ corrections

Towards a Non - Singular Pre - Big Bang Cosmology

We discuss general features of the β-function equations for spatially flat, (d + 1)-dimensional cosmological backgrounds at lowest order in the string-loop expansion, but to all orders in α ′. In the special case of constant curvature and a linear dilaton these equations reduce to (d + 1) algebraic equations in (d + 1) unknowns, whose solutions can act as late-time regularizing attractors for t...

Towards a Non - Singular Pre - Big Bang Cosmologym

We discuss general features of the-function equations for spatially at, (d+1)-dimensional cosmological backgrounds at lowest order in the string-loop expansion, but to all orders in 0. In the special case of constant curvature and a linear dilaton these equations reduce to (d + 1) algebraic equations in (d + 1) unknowns, whose solutions can act as late-time regularizing attractors for the singu...

Non-Standard Big Bang Nucleosynthesis Scenarios

A brief overview of non-standard big bang nucleosynthesis (BBN) scenarios is presented. Trends and results of the light-element nucleosynthesis in BBN scenarios with small-scale or large-scale inhomogeneity, the presence of antimatter domains, stable or unstable massive neutrinos, neutrino oscillations, neutrino degeneracy, or massive decaying particles are summarized.

Rotational inhomogeneities from pre-big bang?

The evolution of the rotational inhomogeneities is investigated in the specific framework of four-dimensional pre-big bang models. While minimal (dilaton-driven) scenarios do not lead to rotational fluctuations, in the case of non-minimal (string-driven) models, fluid sources are present in the pre-big bang phase. The rotational modes of the geometry, coupled to the divergenceless part of the v...

A Brief Summary of Non-standard Big Bang Nucleosynthesis Scenarios