Nonsingular cosmological models with strong gravity in the past
arXiv:2104.13412 · doi:10.1103/PhysRevD.104.063530
Abstract
In scalar-tensor Horndeski theories, nonsingular cosmological models - bounce and genesis - are problematic because of potential ghost and/or gradient instabilities. One way to get around this obstacle is to send the effective Planck mass to zero in the asymptotic past ("strong gravity in the past"). One may suspect that this feature is a signal of a strong coupling problem at early times. However, the classical treatment of the cosmological background is legitimate, provided that the strong coupling energy scale remains at all times much higher than the scale associated with the classical evolution. We construct various models of this sort, namely (i) bouncing Universe which proceeds through inflationary epoch to kination (expansion within general relativity, driven by massless scalar field); (ii) bouncing Universe with kination stage immediately after bounce; (iii) combination of genesis and bounce, with the Universe starting from flat space-time, then contracting and bouncing to the expansion epoch; (iv) "standard" genesis evading the strong coupling problem in the past. All these models are stable, and perturbations about the backgrounds are not superluminal.
arXiv comment40 pages, 15 figures
References in corpus (59)
- k-Inflation
- Generalized G-inflation: Inflation with the most general second-order field equations
- Causality, Analyticity and an IR Obstruction to UV Completion
- Healthy theories beyond Horndeski
- Imperfect Dark Energy from Kinetic Gravity Braiding
- Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability
- Horndeski theory and beyond: a review
- Transforming gravity: from derivative couplings to matter to second-order scalar-tensor theories beyond the Horndeski Lagrangian
- Starting the Universe: Stable Violation of the Null Energy Condition and Non-standard Cosmologies
- G-inflation: inflation driven by the Galileon field
- Towards a Nonsingular Bouncing Cosmology
- Essential Building Blocks of Dark Energy
- Galilean Genesis: an alternative to inflation
- Dark Energy and Modified Gravity in Degenerate Higher-Order Scalar-Tensor (DHOST) theories: a review
- G-Bounce
- Kasner and Mixmaster behavior in universes with equation of state w \ge 1
- The Null Energy Condition and its violation
- Positive Moments for Scattering Amplitudes
- Bouncing Galileon Cosmologies
- Generic instabilities of non-singular cosmologies in Horndeski theory: a no-go theorem
- A Cosmological Super-Bounce
- Classically stable non-singular cosmological bounces
- The Effective Field Theory of nonsingular cosmology
- Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis
- Inflation and primordial non-Gaussianities of "generalized Galileons"
- Fully stable cosmological solutions with a non-singular classical bounce
- Towards Anisotropy-Free and Non-Singular Bounce Cosmology with Scale-invariant Perturbations
- On the local well-posedness of Lovelock and Horndeski theories
- Cosmological Perturbations Through a Non-Singular Ghost-Condensate/Galileon Bounce
- Stability of Geodesically Complete Cosmologies
- A covariant Lagrangian for stable nonsingular bounce
- Subluminal Galilean Genesis
- Primordial non-Gaussianities of gravitational waves in the most general single-field inflation model
- Cosmological bounce and Genesis beyond Horndeski
- G-Bounce Inflation: Towards Nonsingular Inflation Cosmology with Galileon Field
- Galileon Duality
- Non-Singular Bouncing Cosmology: Consistency of the Effective Description
- DBI Realizations of the Pseudo-Conformal Universe and Galilean Genesis Scenarios
- Unbraiding the Bounce: Superluminality around the Corner
- Generalized multi-Galileons, covariantized new terms, and the no-go theorem for non-singular cosmologies
- Galilean Creation of the Inflationary Universe
- From Satisfying to Violating the Null Energy Condition
- Inflation from Minkowski Space
- Towards the nonlinear regime in extensions to GR: assessing possible options
- Cosmological bounces and Lorentzian wormholes in Galileon theories with an extra scalar field
- Unitary null energy condition violation in cosmologies
- Galileon bounce after ekpyrotic contraction
- Generalized Galilean Genesis
- Ultra slow-roll G-inflation
- Genesis with general relativity asymptotics in beyond Horndeski theory
- Non-Gaussian inflationary shapes in theories beyond Horndeski
- Toward evading the strong coupling problem in Horndeski genesis
- Nanohertz gravitational waves from NEC violation in the early universe
- Horndeski genesis: consistency of classical theory
- Well-posedness of cubic Horndeski theories
- Stability and the Gauge Problem in Non-Perturbative Cosmology
- Note on Reheating in G-inflation
- Superluminality in DHOST theory with extra scalar
- Power-law Genesis: strong coupling and galileon-like vector fields
Cited by in corpus (26)
- Pulsar timing array observations as possible hints for nonsingular cosmology
- Generating enhanced parity-violating gravitational waves during inflation with violation of the null energy condition
- Regular black holes, universes without singularities, and phantom-scalar field transitions
- Generating cosmological perturbations in non-singular Horndeski cosmologies
- On the strong coupling problem in cosmologies with "strong gravity in the past"
- Stable cosmological solutions in Horndeski theory
- Stable non-singular cosmologies in beyond Horndeski theory and disformal transformations
- Primordial non-Gaussianity from Galilean Genesis without strong coupling problem
- Black Hole Shadows Constrain Extended Gravity
- Parity violation in primordial tensor non-Gaussianities from matter bounce cosmology
- Null energy condition violation and beyond Horndeski physics in light of DESI DR2 data
- Stability of nonsingular cosmologies in Galileon models with torsion. A no-go theorem for eternal subluminality
- Cuscuton Bounce Beyond the Linear Regime: Bispectrum and Strong Coupling Constraints
- Higher derivative SVT theories from Kaluza-Klein reductions of Horndeski theory
- Can Horndeski Genesis be Nonpathological?
- Healthy Horndeski cosmologies with torsion
- K-inflation: the legitimacy of classical treatment
- Extended Gravity Constraints at Different Scales
- The primordial non-Gaussianities for non-singular Horndeski cosmologies
- Perturbations in Horndeski theory above anisotropic cosmological background
- The Metron Project -- I. The Metron Project Science Program
- Constraining matter-bounce scenario from scalar-induced vector perturbations
- Strong coupling and instabilities in singularity-free inflation from an infinite sum of curvature corrections
- Theoretical filters for shift-symmetric Horndeski gravities
- Crunching, Bouncing, and Cyclical Cosmologies from Dark Sector Interactions
- Non-minimal Effective Scalar-Tensor Gravity in the Early Universe