Nonlinear dynamics of flux compactification

Abstract

We study the nonlinear evolution of unstable flux compactifications, applying numerical relativity techniques to solve the Einstein equations in D dimensions coupled to a q-form field and positive cosmological constant. We show that initially homogeneous flux compactifications are unstable to dynamically forming warped compactifications. In some cases, we find that the warping process can serve as a toy-model of slow-roll inflation, while in other instances, we find solutions that eventually evolve to a singular state. Analogous to dynamical black hole horizons, we use the geometric properties of marginally trapped surfaces to characterize the lower dimensional vacua in the inhomogeneous and dynamical settings we consider. We find that lower-dimensional vacua with a lower expansion rate are dynamically favoured, and in some cases find spacetimes that undergo a period of accelerated expansion followed by contraction.

Evolution of black holes through a nonsingular cosmological bounce

“…Following the growing number of studies making use of techniques from numerical relativity to study cosmological phenomena involving black hole dynamics [44,[55][56][57][58][59][60][61][62], we use numerical solutions to follow the evolution of different size black holes, both non-spinning and spinning, through a bounce, considering those both bigger and smaller than the minimum Hubble radius. Our main results are that the black holes persist to the expanding phase, and that the nonsingular bouncing model under study is fairly robust under large perturbations, in the sense that the local spacetime expansion around the black hole successfully bounces for all of the cases we explored.…”

Evolution of black holes through a nonsingular cosmological bounce

“…Following the growing number of studies making use of techniques from numerical relativity to study cosmological phenomena involving black hole dynamics [42,[51][52][53][54][55][56][57][58], we use numerical solutions to follow the evolution of different size black holes, both non-spinning and spinning, through a bounce, considering those both bigger and smaller than the minimum Hubble radius. Our main results are that the black holes persist to the expanding phase, and that the nonsingular bouncing model under study is fairly robust under large perturbations, in the sense that the local spacetime expansion around the black hole successfully bounces for all of the cases we explored.…”