Swampland Constraints on No-Boundary Quantum Cosmology

Abstract

The Hartle-Hawking no-boundary proposal describes the quantum creation of the universe. To have a non-negligible probability to obtain a classical expanding universe, eternal inflation is required, which is severely constrained by Swampland conjectures such as the refined de Sitter conjecture and the distance conjecture. We discuss this issue in detail and demonstrate the incompatibility. We show that the dimensionless parameters in the refined de Sitter conjecture should be bounded from above by a positive power of the scalar potential to realize the classical expanding universe. In other words, the probability of the classical expanding universe is extremely small under the Swampland conjectures unless the parameters are much smaller than unity. If they are order unity, on the other hand, the saddle-point solution itself ceases to exist implying a genuinely quantum universe.

arXiv comment34 pages, 14 figures; published version, minor corrections in Appendix

References in corpus (89)

• The Standard Model Higgs boson as the inflaton
• On the Geometry of the String Landscape and the Swampland
• The Swampland: Introduction and Review
• Distance and de Sitter Conjectures on the Swampland
• Superconformal Inflationary $\alpha$-Attractors
• Inflationary spacetimes are not past-complete
• On the Cosmological Implications of the String Swampland
• What is the lowest possible reheating temperature?
• Minimal Supergravity Models of Inflation
• Bounds on Slow Roll and the de Sitter Swampland
• The Unity of Cosmological Attractors
• Black Holes and Large N Species Solution to the Hierarchy Problem
• MeV-scale reheating temperature and thermalization of oscillating neutrinos by radiative and hadronic decays of massive particles
• Bounds on very low reheating scenarios after Planck
• De Sitter Space and Eternity
• Starobinsky-like Inflationary Models as Avatars of No-Scale Supergravity
• Trans-Planckian Censorship and the Swampland
• Quantum Gravity Slows Inflation
• Super-Planckian Spatial Field Variations and Quantum Gravity
• The landscape, the swampland and the era of precision cosmology
• The Weak Gravity Conjecture and Scalar Fields
• Trans-Planckian Censorship and Inflationary Cosmology
• Lorentzian Quantum Cosmology
• Quantum Compositeness of Gravity: Black Holes, AdS and Inflation
• On the de Sitter swampland criterion
• The Classical Universes of the No-Boundary Quantum State
• The string swampland constraints require multi-field inflation
• Large Field Inflation and Double $\alpha$-Attractors
• A Measure of de Sitter Entropy and Eternal Inflation
• Backreacted Axion Field Ranges in String Theory
• Quantum Cosmological Perturbations: Predictions and Observations
• The No-Boundary Measure of the Universe
• No smooth beginning for spacetime
• Quantum Break-Time of de Sitter
• The zoo plot meets the swampland: mutual (in)consistency of single-field inflation, string conjectures, and cosmological data
• Single-field $\alpha$-attractors
• Running Kinetic Inflation
• Universality classes of inflation
• Creation of a Compact Topologically Nontrivial Inflationary Universe
• On Exclusion of Positive Cosmological Constant
• No Rescue for the No Boundary Proposal
• Cosmological Attractors from $\alpha$-Scale Supergravity
• Further refining the de Sitter swampland conjecture
• The web of swampland conjectures and the TCC bound
• Quantum Breaking Bound on de Sitter and Swampland
• Repulsive Forces and the Weak Gravity Conjecture
• Linear Inflation from Running Kinetic Term in Supergravity
• Eternal Inflation and the Refined Swampland Conjecture
• Swampland Distance Conjecture, Inflation and $\alpha$-attractors
• Cosmological Attractor Models and Higher Curvature Supergravity
• The large-N running of the spectral index of inflation
• Eternal Inflation and Swampland Conjectures
• Tunneling wave function of the universe
• Rescuing Single Field Inflation from the Swampland
• Avoiding the string swampland in single-field inflation: Excited initial states
• Universality classes for models of inflation
• Distance, de Sitter and Trans-Planckian Censorship conjectures: the status quo of Warm Inflation
• The wave function discord
• Conditions for (No) Eternal Inflation
• The No-Boundary Proposal as a Path Integral with Robin Boundary Conditions
• Generalized Pole Inflation: Hilltop, Natural, and Chaotic Inflationary Attractors
• Steep Eternal Inflation and the Swampland
• Quantum Cosmology and Open Universes
• What is the No-Boundary Wave Function of the Universe?
• No-boundary prescriptions in Lorentzian quantum cosmology
• On the problem of initial conditions for inflation
• A Strong Scalar Weak Gravity Conjecture and Some Implications
• Tunneling wave function of the universe II: the backreaction problem
• Phenomenological Consequences of the Refined Swampland Conjecture
• Eternal Hilltop Inflation
• Stochastic eternal inflation is in the swampland
• Susskind's Challenge to the Hartle-Hawking No-Boundary Proposal and Possible Resolutions
• Loops rescue the no-boundary proposal
• Bouncing Universe from Nothing
• On the Topology of the Inflaton Field in Minimal Supergravity Models
• Space for Both No-Boundary and Tunneling Quantum States of the Universe
• On the No-Boundary Proposal for Ekpyrotic and Cyclic Cosmologies
• The no-boundary proposal in biaxial Bianchi IX minisuperspace
• Eternal Inflation, Entropy Bounds and the Swampland
• Trans-Planckian censorship and single-field inflaton potential
• The no-boundary measure in string theory: Applications to moduli stabilization, flux compactification, and cosmic landscape
• Toward inflation models compatible with the no-boundary proposal
• On the Gauged Kahler Isometry in Minimal Supergravity Models of Inflation
• The entropic quasi-de Sitter instability time from the distance conjecture
• Unstable no-boundary fluctuations from sums over regular metrics
• Is Trans-Planckian Censorship a Swampland Conjecture?
• T-Model Inflation and Bouncing Cosmology
• Eternal Inflation in Swampy Landscapes
• No-boundary wave function for two-field inflation

Cited by in corpus (8)

• Review of the No-Boundary Wave Function
• The Wave Function of Simple Universes, Analytically Continued From Negative to Positive Potentials
• Quantum Cosmology
• Revisiting the no-boundary proposal with a scalar field
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• Dissipative Emergence of Inflation from Quasi-Cyclic Universe
• Dissipative Genesis of the Inflationary Universe
• Wave function of the universe in the presence of trans-Planckian censorship