Stochastic inflation and non-perturbative power spectrum beyond slow roll

Fuente: arXiv
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Auteur principal: Sharma, Devanshu
Format: Preprint
Publié: 2024
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author Sharma, Devanshu
author_facet Sharma, Devanshu
contents Stochastic inflation, together with the $ΔN$ formalism, provides a powerful tool for estimating the large-scale behaviour of primordial fluctuations. In this work, we develop a numerical code to capture the non-perturbative statistics of these fluctuations and validate it to obtain the exponential non-Gaussian tail of the curvature perturbations. We present a numerical algorithm to compute the non-perturbative curvature power spectrum and apply it to both slow-roll (SR) and ultra-slow-roll (USR) single-field models of inflation. We accurately generate a non-perturbative scale-invariant power spectrum in the SR scenario. In the USR case, we obtain a peak in the power spectrum that, in the time-independent regime, aligns with the structure of its perturbative counterpart. Additionally, We underscore how the evolving nature of the super-Hubble perturbations in the USR model complicates the numerical computation of the non-perturbative spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2411_08854
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stochastic inflation and non-perturbative power spectrum beyond slow roll
Sharma, Devanshu
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Stochastic inflation, together with the $ΔN$ formalism, provides a powerful tool for estimating the large-scale behaviour of primordial fluctuations. In this work, we develop a numerical code to capture the non-perturbative statistics of these fluctuations and validate it to obtain the exponential non-Gaussian tail of the curvature perturbations. We present a numerical algorithm to compute the non-perturbative curvature power spectrum and apply it to both slow-roll (SR) and ultra-slow-roll (USR) single-field models of inflation. We accurately generate a non-perturbative scale-invariant power spectrum in the SR scenario. In the USR case, we obtain a peak in the power spectrum that, in the time-independent regime, aligns with the structure of its perturbative counterpart. Additionally, We underscore how the evolving nature of the super-Hubble perturbations in the USR model complicates the numerical computation of the non-perturbative spectrum.
title Stochastic inflation and non-perturbative power spectrum beyond slow roll
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2411.08854