publication . Article . Preprint . 2014

Simulating the universe(s) II: phenomenology of cosmic bubble collisions in full general relativity

Wainwright, Carroll L.; Johnson, Matthew C.; Aguirre, Anthony; Peiris, Hiranya V.;
Open Access
  • Published: 13 Oct 2014
  • Publisher: IOP Publishing
Abstract
Observing the relics of collisions between bubble universes would provide direct evidence for the existence of an eternally inflating Multiverse; the non-observation of such events can also provide important constraints on inflationary physics. Realizing these prospects requires quantitative predictions for observables from the properties of the possible scalar field Lagrangians underlying eternal inflation. Building on previous work, we establish this connection in detail. We perform a fully relativistic numerical study of the phenomenology of bubble collisions in models with a single scalar field, computing the comoving curvature perturbation produced in a wide variety of models. We also construct a set of analytic predictions, allowing us to identify the phenomenologically relevant properties of the scalar field Lagrangian. The agreement between the analytic predictions and numerics in the relevant regions is excellent, and allows us to generalize our results beyond the models we adopt for the numerical studies. Specifically, the signature is completely determined by the spatial profile of the colliding bubble just before the collision, and the de Sitter invariant distance between the bubble centers. The analytic and numerical results support a power-law fit with an index $1< \kappa \lesssim 2$. For collisions between identical bubbles, we establish a lower-bound on the observed amplitude of collisions that is set by the present energy density in curvature.
Comment: 35 pages, 17 figures
Persistent Identifiers
Subjects
arXiv: General Relativity and Quantum Cosmology
free text keywords: Astronomy and Astrophysics, High Energy Physics - Theory, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology, Eternal inflation, Theoretical physics, De Sitter universe, Scalar field, Cosmological perturbation theory, General relativity, Physics, Inflation (cosmology), Phenomenology (particle physics), De Sitter space
Funded by
EC| COSMICDAWN
Project
COSMICDAWN
Understanding the Origin of Cosmic Structure
  • Funder: European Commission (EC)
  • Project Code: 306478
  • Funding stream: FP7 | SP2 | ERC
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