Séminaire / Seminar GReCO |
| « Time-reversed Stochastic Inflation » |
|
Christophe Ringeval |
|
Cosmic inflation may exhibit stochastic periods during which quantum
fluctuations dominate over the semi-classical evolution, arguably triggering an eternal regime associated with strong inhomogeneities. We present a time-reversed approach to stochastic inflation, based on a reverse Fokker-Planck equation, which allows us to derive non-perturbatively the probability distribution of the field values at a given time before the end of the quantum regime. As a motivated example, we solve the pathological flat semi-infinite potential, having a drift term or not, and derive a new and exact formula for the probability distribution of the quantum-generated curvature fluctuations. This one is always normalisable, exhibiting either exponential or Levy tails according to the drift value. Large inhomogeneities therefore exist but our result shows that nothing really bad happens when inflation becomes purely quantum. |
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lundi 2 février 2026 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |