Gravitational decoupling and the Picard-Lefschetz approach
| Autor: | Alex Cole, Gary Shiu, William Cottrell, Jon Brown |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Physical Review |
| ISSN: | 2470-0029 2470-0010 |
| DOI: | 10.1103/physrevd.97.025002 |
| Popis: | In this work, we consider tunneling between nonmetastable states in gravitational theories. Such processes arise in various contexts, e.g., in inflationary scenarios where the inflaton potential involves multiple fields or multiple branches. They are also relevant for bubble wall nucleation in some cosmological settings. However, we show that the transition amplitudes computed using the Euclidean method generally do not approach the corresponding field theory limit as Mp→∞. This implies that in the Euclidean framework, there is no systematic expansion in powers of GN for such processes. Such considerations also carry over directly to no-boundary scenarios involving Hawking-Turok instantons. In this note, we illustrate this failure of decoupling in the Euclidean approach with a simple model of axion monodromy and then argue that the situation can be remedied with a Lorentzian prescription such as the Picard-Lefschetz theory. As a proof of concept, we illustrate with a simple model how tunneling transition amplitudes can be calculated using the Picard-Lefschetz approach. |
| Databáze: | OpenAIRE |
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