A manifestly covariant theory of multifield stochastic inflation in phase space: solving the discretisation ambiguity in stochastic inflation

@article{Pinol2020AMC,
  title={A manifestly covariant theory of multifield stochastic inflation in phase space: solving the discretisation ambiguity in stochastic inflation},
  author={Lucas Pinol and S'ebastien Renaux-Petel and Yuichiro Tada},
  journal={Journal of Cosmology and Astroparticle Physics},
  year={2020},
  volume={2021}
}
Stochastic inflation is an effective theory describing the super-Hubble, coarse-grained, scalar fields driving inflation, by a set of Langevin equations. We previously highlighted the difficulty of deriving a theory of stochastic inflation that is invariant under field redefinitions, and the link with the ambiguity of discretisation schemes defining stochastic differential equations. In this paper, we solve the issue of these "inflationary stochastic anomalies" by using the Stratonovich… 
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
Statistics of coarse-grained cosmological fields in stochastic inflation
We present a generic framework to compute the one-point statistics of cosmological perturbations, when coarse-grained at an arbitrary scale R, in the presence of quantum diffusion. Making use of the
Primordial gravitational waves from excited states
We show that a scalar excited state with large occupation numbers during inflation leads to an enhancement of tensor modes and a characteristic pattern of order-one oscillations in the associated
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 Stochastic Gravitational Wave Background Anisotropies: in-in Formalization and Applications
. Primordial non-Gaussianities of the scalar(tensor)-tensor-tensor type supporting a non-trivial squeezed component are known to induce anisotropies in the stochastic gravitational wave background.
Quantum Effects in Cosmology
Quantum effects play an essential role in modern cosmology. Perhaps the most striking example comes from large-scale structures, generally assumed to originate from vacuum quantum fluctuations and
The hand-made tail: non-perturbative tails from multifield inflation
Abstract It is becoming increasingly clear that large but rare fluctuations of the primordial curvature field, controlled by the tail of its probability distribution, could have dramatic effects on
Symplectic Quantization I: Dynamics of Quantum Fluctuations in a Relativistic Field Theory
We propose here a new symplectic quantization scheme, where quantum fluctuations of a scalar field theory stem from two main assumptions: relativistic invariance and equiprobability of the field
2 7 M ay 2 02 1 Symplectic quantization II : dynamics of space-time quantum fluctuations and the cosmological constant
The symplectic quantization scheme proposed for matter scalar fields in the companion paper [1] is generalized here to the case of space-time quantum fluctuations. That is, we present a new formalism
Non-Gaussian Tail of the Curvature Perturbation in Stochastic Ultraslow-Roll Inflation: Implications for Primordial Black Hole Production.
TLDR
Studying the production of primordial black holes in a viable model, it is found that stochastic effects during USR increase their abundance by a factor of ∼10^{5} compared with the Gaussian approximation.
...
1
2
3
...

References

SHOWING 1-10 OF 249 REFERENCES
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,
Revisiting non-Gaussianity in multifield inflation with curved field space
Recent studies of inflation with multiple scalar fields have highlighted the importance of non-canonical kinetic terms in novel types of inflationary solutions. This motivates a thorough analysis of
Stochastic inflation revisited: non-slow-roll statistics and DBI inflation
Stochastic inflation describes the global structure of the inflationary universe by modeling the super-Hubble dynamics as a system of matter fields coupled to gravity where the sub-Hubble field
Lagrangian formulation of stochastic inflation: Langevin equations, one-loop corrections and a proposed recursive approach
We present a new, recursive approach to stochastic inflation which is self-consistent and solves multiple problems which plagued a certain number of previous studies, in particular in realistic
Lagrangian Formulation of Stochastic Inflation: A Recursive Approach
We present a new, recursive approach to stochastic inflation which is self-consistent and solves multiple problems which plagued a certain number of previous studies, in particular in realistic
Stochastic inflation in phase space: Is slow roll a stochastic attractor?
An appealing feature of inflationary cosmology is the presence of a phase-space attractor, "slow roll", which washes out the dependence on initial field velocities. We investigate the robustness of
Stochastic Dynamics of Infrared Fluctuations in Accelerating Universe
We extend investigations of infrared dynamics in accelerating universes. In the presence of massless and minimally coupled scalar fields, physical quantities may acquire growing time dependences
Constraints on Holographic Multifield Inflation and Models Based on the Hamilton-Jacobi Formalism.
TLDR
The absence of underdamped oscillations implies that a detection of "cosmological collider" oscillatory patterns in the non-Gaussian bispectrum would not only rule out single-field inflation, but also holographic inflation or any inflationary model based on the Hamilton-Jacobi equations.
Functional renormalization group for stochastic inflation
We apply the functional renormalization group to Starobinsky's stochastic equation describing the local dynamics of a light scalar field in de Sitter. After elaborating on the over-damped regime of
...
1
2
3
4
5
...