A classical, non-singular, bouncing universe

Abstract

We present a model for a classical, non-singular bouncing cosmology without violation of the null energy condition (NEC). The field content is General Relativity plus a real scalar field with a canonical kinetic term and only renormalizable, polynomial type self-interaction for the scalar field in the Jordan frame. The universe begins vacuum-energy dominated and is contracting at $t=-\infty$. We consider a closed universe with a positive spatial curvature, which is responsible for the universe bouncing without any NEC violation. An $R{\varphi }^2$ coupling between the Ricci scalar and the scalar field drives the scalar from the initial false vacuum to the true vacuum during the bounce. The model is sub-Planckian throughout its evolution and every dimensionful parameter is below the effective field theory scale $M_P$, so we expect no ghost-type or tachyonic instabilities. This model solves the horizon problem and extends co-moving particle geodesics to past infinity, resulting in a geodesically complete universe without singularities. We solve the Friedman equations and the scalar field equation of motion numerically, and analytically under certain approximations.

19 pages, 5 figures

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Cited by in corpus (8)

• Scalar and Tensor Perturbations in DHOST Bounce Cosmology
• Lorentzian Vacuum Transitions: Open or Closed Universes?
• Bouncing Cosmological Isotropic Solutions in Scalar-Tensor Gravity
• Implementation of cosmological bounce inflation with Nojiri-Odintsov generalized holographic dark fluid
• Transitioning from a bounce to $R^2$ inflation
• A non-singular closed bouncing universe without violation of null energy condition
• Feasibility of singularity avoidance for a collapsing object due to a scalar field
• Bouncing cosmologies from Born-Infeld-type gravity