Can gravitational instantons really constrain axion inflation?

• Verfasst von: Hebecker, Arthur [VerfasserIn]
• Verfasst von: Mangat, Patrick [VerfasserIn]
• Verfasst von: Witkowski, Lukas T. [VerfasserIn]
• Titel: Can gravitational instantons really constrain axion inflation?
• Verf.angabe: Arthur Hebecker, Patrick Mangat, Stefan Theisen, Lukas T. Witkowski
• E-Jahr: 2017
• Jahr: 22 July 2016
• Umfang: 66 S.
• Fussnoten: Identifizierung der Ressource nach: Last revised 16 Feb 2017 ; Gesehen am 16.12.2020
• Titel Quelle: Enthalten in: De.arxiv.org
• Ort Quelle: [S.l.] : Arxiv.org, 1991
• Jahr Quelle: 2016
• Band/Heft Quelle: (2016) Artikel-Nummer 1607.06814, 66 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: High Energy Physics - Theory
• Sach-SW: General Relativity and Quantum Cosmology
• K10plus-PPN: 1565763270

Abstract

Axions play a central role in inflationary model building and other cosmological applications. This is mainly due to their flat potential, which is protected by a global shift symmetry. However, quantum gravity is known to break global symmetries, the crucial effect in the present context being gravitational instantons or Giddings-Strominger wormholes. We attempt to quantify, as model-independently as possible, how large a scalar potential is induced by this general quantum gravity effect. We pay particular attention to the crucial issue which solutions can or cannot be trusted in the presence of a moduli-stabilisation and a Kaluza-Klein scale. An important conclusion is that, due to specific numerical prefactors, the effect is surprisingly small even in UV-completions with the highest possible scale offered by string theory. As we go along, we discuss in detail Euclidean wormholes, cored and extremal instantons, and how the latter arise from 5d Reissner-Nordstrom black holes. We attempt to dispel possible doubts that wormholes contribute to the scalar potential by an explicit calculation. We analyse the role of stabilised dilaton-like moduli. Finally, we argue that Euclidean wormholes may be the objects satisfying the Weak Gravity Conjecture extended to instantons.