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Critical Number of Fields in Stochastic Inflation
Vincent Vennin1, Hooshyar Assadullahi1,2, Hassan Firouzjahi3
1Institute of Cosmology & Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX, United Kingdom.
Physical Review Letters
|February 4, 2017
Summary
Stochastic effects in multifield inflation can lead to infinite inflationary e-folds and correlation functions. Regularization methods and multifield models offer insights into quantum effects on cosmological fluctuations.
Area of Science:
- Cosmology
- Theoretical Physics
- Quantum Field Theory
Background:
- Inflationary cosmology is a leading paradigm for the early universe.
- Stochastic effects and multifield dynamics are crucial for understanding primordial fluctuations.
- The stochastic δN formalism connects inflationary dynamics to curvature perturbations.
Purpose of the Study:
- Investigate stochastic effects in multifield inflation.
- Calculate statistical moments of inflationary e-folds using first passage time techniques.
- Analyze the impact of the number of fields on inflationary dynamics and correlation functions.
Main Methods:
- Employ first passage time techniques to compute statistical moments of e-folds.
- Utilize the stochastic δN formalism to derive correlation functions of primordial curvature perturbations.
- Explore the role of potential shape and number of fields in inflationary scenarios.
Main Results:
- The number of fields is critical; multifield inflation allows exploration of large-field regions.
- Mean e-folds and correlation functions can become infinite for certain potentials and field numbers.
- Regularization with reflecting/absorbing walls yields well-defined, cutoff-independent results.
- Multifield models exhibit significant stochastic corrections even at sub-Planckian energies.
Conclusions:
- Multifield inflation presents unique stochastic phenomena compared to single-field models.
- Regularization techniques provide a consistent framework for handling divergences.
- These findings open avenues for probing quantum effects in the early universe through cosmological observations.
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