Stochastic approaches to inflation model building

Abstract

While inflation gives an appealing explanation of observed cosmological data, there are a wide range of different inflation models, providing differing predictions for the initial perturbations. Typically models are motivated either by fundamental physics considerations or by simplicity. An alternative is to generate large numbers of models via a random generation process, such as the flow equations approach. The flow equations approach is known to predict a definite structure to the observational predictions. In this paper, we first demonstrate a more efficient implementation of the flow equations exploiting an analytic solution found by Liddle (2003). We then consider alternative stochastic methods of generating large numbers of inflation models, with the aim of testing whether the structures generated by the flow equations are robust. We find that while typically there remains some concentration of points in the observable plane under the different methods, there is significant variation in the predictions amongst the methods considered.

7 pages RevTeX4 with 7 figures. Updated to match version accepted by PRD. Calculations extended to sixth-order and extra clarifications added

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• Implications of the Curvaton on Inflationary Cosmology
• The Effective Theory of Inflation in the Standard Model of the Universe and the CMB+LSS data analysis
• Horizon-Flow off-track for Inflation
• Dynamics of the Inflationary Flow Equations
• Shortcomings of New Parametrizations of Inflation
• The Hubble Slow Roll Expansion for Multi Field Inflation
• Let Effective Field Theory of Inflation flow: stochastic generation of models with red/blue tensor tilt
• New Solutions of the Inflationary Flow Equations
• Pitfalls of a power-law parameterization of the primordial power spectrum for Primordial Black Hole formation
• Flows into inflation: An effective field theory approach
• Plateau Inflation from Random Non-Minimal Coupling
• Flow equations in generalized braneworld scenarios
• Inflation model building with an accurate measure of e-folding