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.

34 pages, 14 figures; published version, minor corrections in Appendix

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Cited by in corpus (7)

• Review of the No-Boundary Wave Function
• The Wave Function of Simple Universes, Analytically Continued From Negative to Positive Potentials
• 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