Numerical study of inhomogeneous pre-big-bang inflationary cosmology

Abstract

We study numerically the inhomogeneous pre-big-bang inflation in a spherically symmetric space-time. We find that a large initial inhomogeneity suppresses the onset of the pre-big-bang inflation. We also find that even if the pre-big-bang inflationary stage is realized, the initial inhomogeneities are not homogenized. Namely, during the pre-big-bang inflation "hairs"(irregularities) do not fall, in sharp contrast to the usual (potential energy dominated) inflation where initial inhomogeneity and anisotropy are damped and thus the resulting universe is less sensitive to initial conditions.

Physically motivated uncertainty relations at the Planck length for an emergent non-commutative spacetime

“…For this reason, we resort to the so-called hoop conjecture (see [23,[31][32][33][34][35][36][37]). In its original version, it states that • horizons form when and only when a mass M is concentrated into a region whose circumference in every direction satisfies C 4πM G c 2 .…”

Non-Abelian T-duality in pre-big-bang cosmology

“…However, this requires a non trivial mechanism for matching these two branches. We refer the reader to [4,5,6,7,8,9] for more details on this subject.…”

“…Higher order contributions in α ′ might be able to deal with the high curvature states typical of a big-bang singularity. The problem of regularization of the big-bang singularity (the graceful exit problem) by means of higher α ′ contributions have been theoretically investigated in [4,5,6] and numerically in [7,8,9]. These studies indicate that the pre-big-bang cosmology could provide the necessary phase of inflation as well as a solution to the pre-big-bang singularity.…”

Quantum potentiality in Inhomogeneous Cosmology

“…Inhomogeneous cosmological models are exact spacetimes which in general do not admit any isometry vector field while the conditions described by the cosmological principle, that is, the limit of the Friedmann-Lemaître-Robertson-Walker universe is provided [10]. Inhomogeneous cosmological models can be used for the description of the universe in the preinflationary era [11][12][13][14][15], as also in the description of the small inhomogeneities which are found by cosmological observations [16][17][18][19][20]. This is an alternative approach based on exact solutions and is different from the cosmological perturbation theory.…”