The robustness of slow contraction and the shape of the scalar field potential

Abstract

We use numerical relativity simulations to explore the conditions for a canonical scalar field $\varphi$ minimally coupled to Einstein gravity to generate an extended phase of slow contraction that robustly smooths the universe for a wide range of initial conditions and then sets the conditions for a graceful exit stage. We show that to achieve robustness it suffices that the potential $V(\varphi )$ is negative and $M_{\mathrm{Pl}}|V_{,\varphi }/V|\gtrsim 5$ during the smoothing phase. We also show that, to exit slow contraction, the potential must have a minimum. Beyond the minimum, we find no constraint on the uphill slope including the possibility of ending on a positive potential plateau or a local minimum with $V_{\min }>0$. Our study establishes ultralocality for a wide range of potentials as a key both to robust smoothing and to graceful exit.

arXiv comment23 pages, 7 figures

References in corpus (16)

• On the Geometry of the String Landscape and the Swampland
• Distance and de Sitter Conjectures on the Swampland
• On the Cosmological Implications of the String Swampland
• Infinite Distances in Field Space and Massless Towers of States
• G-Bounce
• Kasner and Mixmaster behavior in universes with equation of state w \ge 1
• A new kind of cyclic universe
• Fully stable cosmological solutions with a non-singular classical bounce
• Evolution to a smooth universe in an ekpyrotic contracting phase with w > 1
• Cosmological bounce and Genesis beyond Horndeski
• Supersmoothing through Slow Contraction
• Robustness of slow contraction to cosmic initial conditions
• Ultralocality and Slow Contraction
• The Effects of Multiple Modes and Reduced Symmetry on the Rapidity and Robustness of Slow Contraction
• Contracting Cosmologies and the Swampland
• Numerical Relativity as a New Tool for Fundamental Cosmology

Cited by in corpus (1)

• Negative scalar potentials and the swampland: an Anti-Trans-Planckian Censorship Conjecture