Generation of fluctuations during inflation: Comparison of stochastic and field-theoretic approaches

@article{Finelli2009GenerationOF,
  title={Generation of fluctuations during inflation: Comparison of stochastic and field-theoretic approaches},
  author={Fabio Finelli and G. Marozzi and Alexei A. Starobinsky and Gian Paolo Vacca and Giovanni Venturi},
  journal={Physical Review D},
  year={2009},
  volume={79},
  pages={044007-044007}
}
We prove that the stochastic and standard field-theoretical approaches produce exactly the same results for the amount of light massive scalar field fluctuations generated during inflation in the leading order of the slow-roll approximation. This is true both in the case for which this field is a test one and inflation is driven by another field, and the case for which the field plays the role of inflaton itself. In the latter case, in order to calculate the mean square of the gauge-invariant… 
Stochastic Inflation at NNLO
Abstract Stochastic Inflation is an important framework for understanding the physics of de Sitter space and the phenomenology of inflation. In the leading approximation, this approach results in a
Inflationary stochastic anomalies
The stochastic approach aims at describing the long-wavelength part of quantum fields during inflation by a classical stochastic theory. It is usually formulated in terms of Langevin equations,
Power spectrum in stochastic inflation
We compute the power spectrum of curvature perturbations in stochastic inflation. This combines the distribution of first crossing times through the end-of-inflation surface, which has been
Quantum phase of inflation
Inflation models can have an early phase of inflation where the evolution of the inflaton is driven by quantum fluctuations before entering the phase driven by the slope of the scalar field
Stochastic inflation beyond slow roll
We study the stochastic formalism of inflation beyond the usual slow-roll approximation. We verify that the assumptions on which the stochastic formalism relies still hold even far from the slow-roll
Multiple Fields in Stochastic Inflation
Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary
Evolution of vacuum fluctuations generated during and before inflation
We calculate the time evolution of the expectation value of the energy-momentum tensor for a minimally coupled massless scalar field in cosmological spacetimes, with an application to dark energy in
Stochastic approach to gravitational waves from inflation
We propose a coarse-graining procedure for describing the superhorizon dynamics of inflationary tensor modes. Our aim is to formulate a stochastic description for the statistics of spin-2 modes which
A Tail of Eternal Inflation
Non-trivial inflaton self-interactions can yield calculable signatures of primordial nonGaussianity that are measurable in cosmic surveys. Surprisingly, we find that the phase transition to slow-roll
Primordial Fluctuations in String Cosmology
This thesis is dedicated to the study of inflationary scenarios based on string theory. Inflation is a brief period of accelerated expansion in the very early Universe which gives natural
...
...

References

SHOWING 1-10 OF 37 REFERENCES
Solving stochastic inflation for arbitrary potentials
A perturbative method for solving the Langevin equation of inflationary cosmology in the presence of backreaction is presented. In the Gaussian approximation, the method permits an explicit
On the divergences of inflationary superhorizon perturbations
We discuss the infrared divergences that appear to plague cosmological perturbation theory. We show that, within the stochastic framework, they are regulated by eternal inflation so that the theory
Gravitational particle production and the moduli problem
A theory of gravitational production of light scalar particles during and after inflation is investigated. We show that in the most interesting cases where long-wavelength fluctuations of light
STOCHASTIC DE SITTER (INFLATIONARY) STAGE IN THE EARLY UNIVERSE
The dynamics of a large-scale quasi-homogeneous scalar field producing the de Sitter (inflationary) stage in the early universe is strongly affected by small-scale quantum fluctuations of the same
A General Analytic Formula for the Spectral Index of the Density Perturbations Produced during Inflation.
During inflation'> vacuum fluctuations on scales less than the Hubble radius in scalar fields with effective masses much less than the Hubble parameter**> are magnified into classical perturbations
Analysis of inflation driven by a scalar field and a curvature-squared term.
TLDR
The spectrum of adiabatic perturbations generated from vacuum quantum fluctuations is investigated and it is found that it is quasiflat (though not necessarily varying monotonically with scale) in the case of single inflation; for double inflation, it has a characteristic step.
The Three-Point Correlation Function of the Cosmic Microwave Background in Inflationary Models
We analyze the temperature three–point correlation function and the skewness of the Cosmic Microwave Background (CMB), providing general relations in terms of multipole coefficients. We then focus on
Energy-momentum tensor of field fluctuations in massive chaotic inflation
We study the renormalized energy-momentum tensor (EMT) of the inflaton fluctuations in rigid space-times during the slow-rollover regime for chaotic inflation with a mass term. We use dimensional
Backreaction of cosmological fluctuations during power-law inflation
We study the renormalized energy-momentum tensor of cosmological scalar fluctuations during the slow-rollover regime for power-law inflation and find that it is characterized by a negative energy
...
...