The boundary proposal

• Verfasst von: Friedrich, Björn Steven [VerfasserIn]
• Verfasst von: Hebecker, Arthur [VerfasserIn]
• Titel: The boundary proposal
• Verf.angabe: Bjoern Friedrich, Arthur Hebecker
• E-Jahr: 2024
• Jahr: September 2024
• Umfang: 7 S.
• Illustrationen: Illustrationen
• Fussnoten: Online verfügbar: 8. August 2024, Artikelversion: 9. August 2024 ; Gesehen am 20.03.2025
• Titel Quelle: Enthalten in: Physics letters
• Ort Quelle: Amsterdam : North-Holland Publ., 1967
• Jahr Quelle: 2024
• Band/Heft Quelle: 856(2024) vom: Sept., Artikel-ID 138946, Seite 1-7
• ISSN Quelle: 1873-2445
• DOI: doi:10.1016/j.physletb.2024.138946
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1920154221

Abstract

One of the leading ideas for the beginning of the Universe is the Hartle-Hawking ‘No-Boundary Proposal.’ Since the Cobordism Conjecture claims that any spacetime allows for a dynamical boundary, we suggest that one may equally well consider a ‘Boundary Proposal’. Specifically, the corresponding euclidean instanton is a sphere with two holes around north and south pole cut out. Analogously to the Hartle-Hawking proposal, the sphere is then cut in two at the equator and half of it is dropped. The equator is glued to an expanding Lorentzian de Sitter space, implementing a beginning of the Universe with a spacelike spherical boundary at its earliest moment. This process is in principle on equal footing with the one based on the no-boundary instanton. In fact, if the Linde-Vilenkin sign choice is used, this ‘Boundary’ creation process may even dominate. An intriguing implication arises if tensionless end-of-the-world branes, as familiar from type-IIA or M-theory, are available: Analogously to the Boundary Proposal, one may then be able to create a compact, flat torus universe from nothing, without any exponential suppression or enhancement factors.