arXiv 1606.033432016-06astro-ph.COgr-qchep-phhep-th

Consistency relation and inflaton field redefinition in the delta N formalism

Guillem Domenech, Jinn-Ouk Gong, Misao Sasaki

备注：: (v1) 10 pages; (v2) references added, to appear in Physics Letters B
DOI：: 10.1016/j.physletb.2017.04.014

英文摘要：

We compute for general single-field inflation the intrinsic non-Gaussianity due to the self-interactions of the inflaton field in the squeezed limit. We recover the consistency relation in the context of the delta N formalism, and argue that there is a particular field redefinition that makes the intrinsic non-Gaussianity vanishing, thus improving the estimate of the local non-Gaussianity using the delta N formalism.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

一种有效的宇宙学对撞机

An Effective Cosmological Collider

该论文通过建立阿贝尔规范-希格斯-暴胀子有效场论的最小算符基，系统研究了重粒子有效场论中的算符冗余，识别出具有潜在宇宙学对撞机信号的新非冗余算符，并推广至其他相关理论。

2024-01-19astro-ph.COhep-phhep-th

Delta-N formalism for the evolution of the curvature perturbations in generalized multi-field inflation

The delta-N formalism is considered to calculate the evolution of the curvature perturbation in generalized multi-field inflation models. The result is consistent with the usual calculation of the standard kinetic term. For the calculation of the generalized kinetic term, we improved the definition of the adiabatic field. Our calculation improves the usual calculation of the evolution of the curvature perturbations based on the field equations and the perturbations, giving a very simple and intuitive argument for the evolution equations in terms of the perturbations of the inflaton velocity. S…

2009-11-02astro-ph.COgr-qchep-ph

$β$-function formalism for inflationary models with a non minimal coupling with gravity

We discuss the introduction of a non minimal coupling between the inflaton and gravity in terms of the recently proposed $β$-function formalism for inflation\cite{Binetruy:2014zya}. Via a field redefinition we reduce to the case of minimally coupled theories. The universal attractor at strong coupling has a simple explanation in terms of the new field. Generalizations are discussed and the possibility of evading the universal attractor is shown.

2016-01-22astro-ph.COgr-qchep-ph

Effects of the imaginary inflaton component in supergravity new inflation

When models of new inflation are implemented in supergravity, the inflaton is a complex and not a real scalar field. As a complex scalar field has two independent components, supergravity models of new inflation are naturally two-field models. In this paper, we use the delta N formalism to analyse how the two-field behaviour modifies the usual single-field predictions. We find that the model reduces to the single-field limit if the inflaton mass term is sufficiently small. Otherwise, the imaginary inflaton component reduces the amplitude A_s and the spectral index n_s of the scalar curvature p…

2013-11-12astro-ph.COhep-ph

Inflationary Infrared Divergences: Geometry of the Reheating Surface vs. delta N Formalism

We describe a simple way of incorporating fluctuations of the Hubble scale during the horizon exit of scalar perturbations into the delta N formalism. The dominant effect comes from the dependence of the Hubble scale on low-frequency modes of the inflaton. This modifies the coefficient of the log-enhanced term appearing in the curvature spectrum at second order in field fluctuations. With this modification, the relevant coefficient turns out to be proportional to the second derivative of the tree-level spectrum with respect to the inflaton phi at horizon exit. A logarithm with precisely the sa…

2010-08-11astro-ph.COhep-th

Primordial black hole formation with non-Gaussian curvature perturbations

In the context of transient constant-roll inflation near a local maximum, we derive the non-perturbative field redefinition that relates a Gaussian random field with the true non-Gaussian curvature perturbation. Our analysis shows the emergence of a new critical amplitude $ζ_*$, corresponding to perturbations that prevent the inflaton from overshooting the local maximum, thus becoming trapped in the false minimum of the potential. For potentials with a mild curvature at the local maximum (and thus small non-Gaussianity), we recover the known perturbative field redefinition. We apply these resu…

2019-07-09astro-ph.COhep-th

更多相关论文收起更多论文

Hilltop inflation with preinflation from coupling to matter fields

We propose a class of models of supersymmetric hilltop inflation (also called "new inflation") where the initial conditions of the inflaton close to the hilltop are generated through "matter field preinflation". This is achieved via a coupling term between the inflaton and matter fields (i.e. Standard Model fields or a right-handed neutrino). The same coupling also opens up a decay channel for the inflaton into Standard Model fields, which allows efficient reheating of the universe. We discuss the multifield dynamics of the inflaton and matter fields during inflation using the delta N formalis…

2014-05-28astro-ph.COhep-ph

Dark matter and dark energy from pockets of gravity created by quantum tunneling of the inflaton potential

It is usually assumed that during the reheating period of inflation the inflaton field behaves coherently and follows a classical path. It is pointed out that a background inflaton field ϕ_0 falling down a potential density V(ϕ) can and frequently should undergo a quantum tunneling effect involving an energy \DeltaV<<V, so that it becomes possible to create perturbative inflatons ϕ's, which, in turn, can disintegrate into other particles. We argue for this scenario using large field inflation assumed during a typical slow-roll regime, and typical values for the physical quantities associated w…

2013-12-13astro-ph.COgr-qchep-th

Consistency of inflation and preheating in F(R) supergravity

We study inflation and preheating in F(R) supergravity characterized by two mass scales of a scalar degree of freedom (scalaron): M (associated with the inflationary era) and m (associated with the preheating era). The allowed values of the masses M and m are derived from the amplitude of the CMB temperature anisotropies. We show that our model is consistent with the joint observational constraints of WMAP and other measurements in the regime where a sufficient amount of inflation (with the number of e-foldings larger than 50) is realized. In the low-energy regime relevant to preheating, we de…

2012-07-20astro-ph.COgr-qchep-ph

A note on the role of the boundary terms for the non-Gaussianity in general k-inflation

In this short note we clarify the role of the boundary terms in the calculation of the leading order tree-level bispectrum in a fairly general minimally coupled single field inflationary model, where the inflaton's Lagrangian is a general function of the scalar field and its first derivatives. This includes k-inflation, DBI-inflation and standard kinetic term inflation as particular cases. These boundary terms appear when simplifying the third order action by using integrations by parts. We perform the calculation in the comoving gauge obtaining explicitly all total time derivative interaction…

2011-06-29astro-ph.COgr-qchep-th

VCDM 中来自暴胀/反弹宇宙的双谱

Bispectrum from inflation/bouncing Universe in VCDM

本文研究了 VCDM（II 型极小修改引力）模型在暴胀和反弹宇宙中的非线性相互作用与双谱，发现当 VCDM 势主导时双谱会偏离标准结果并可能违反 Maldacena 一致性关系，而反弹模型的双谱仍满足观测约束，未来局部非高斯性测量可检验该模型。

2024-07-25astro-ph.COgr-qchep-th

关于原初黑洞形成中单场暴胀的双谱及单圈修正的注记

Note on the bispectrum and one-loop corrections in single-field inflation with primordial black hole formation

本文研究单场暴胀中通过势能平坦区实现超慢滚动从而形成原初黑洞的机制，计算曲率扰动双谱并验证其满足马尔达塞纳定理，同时用源方法计算功率谱的单圈修正，结果与in-in微扰论二阶展开一致。

2024-05-20astro-ph.COhep-th

Single-field inflation constraints from CMB and SDSS data

We present constraints on canonical single-field inflation derived from WMAP five year, ACBAR, QUAD, BICEP data combined with the halo power spectrum from SDSS LRG7. Models with a non-scale-invariant spectrum and a red tilt n_s < 1 are now preferred over the Harrison-Zel'dovich model (n_s = 1, tensor-to-scalar ratio r = 0) at high significance. Assuming no running of the spectral indices, we derive constraints on the parameters (n_s, r) and compare our results with the predictions of simple inflationary models. The marginalised credible intervals read n_s = 0.962^{+0.028}_{-0.026} and r < 0.17…

2010-04-14astro-ph.COhep-ph

Primordial Black Holes and Local Non-Gaussianity in Canonical Inflation

Primordial black holes (PBHs) cannot be produced abundantly enough to be the dark matter in canonical single-field inflation under slow roll. This conclusion is robust to local non-Gaussian correlations between long- and short-wavelength curvature modes, which we show have no effect in slow roll on local primordial black hole abundances. For the prototypical model which evades this no go, ultra-slow roll (USR), these squeezed non-Gaussian correlations have at most an order unity effect on the variance of PBH-producing curvature fluctuations for models that would otherwise fail to form sufficie…

2019-02-26astro-ph.COgr-qchep-th

Non-Gaussianity from Step Features in the Inflationary Potential

We provide analytic solutions for the power spectrum and bispectrum of curvature fluctuations produced by a step feature in the inflaton potential, valid in the limit that the step is short and sharp. In this limit, the bispectrum is strongly scale dependent and its effective non-linearity attains a large oscillatory amplitude. The perturbations to the curvature power spectrum, on the other hand, remain a small component on top of the usual spectrum of fluctuations generated by slow roll. We utilize our analytic solutions to assess the observability of the predicted non-Gaussian signatures and…

2012-02-29astro-ph.COhep-th