Large non-Gaussianities with intermediate shapes from quasi-single-field inflation

By Xingang Chen, Yi Wang. 2009

345 citations recorded by the source corpus.

We study the slow-roll inflation models, where the inflaton slow-rolls along a trajectory whose orthogonal directions are lifted by potentials with masses of order the Hubble parameter. In these models large non-Gaussianities can be generated through the transformation from the isocurvature modes to the curvature mode, once the inflaton trajectory turns. We find large bispectra with a one-parameter family of novel shapes, interpolating between the equilateral and local shape. According to the in-in formalism, the shapes of these non-Gaussianities are different from a simple projection from the isocurvature non-Gaussian correlation functions.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c681c6dc44bfc3464e046d87ed6edb6844dcc2a4

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In Astronomy and Astrophysics

Citations in the corpus

Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, background): “In the quasisingle-field case with mass m ∼ H isocurvature modes, a detailed investigation of the ongoing conversion into the curvature mode demonstrated that novel shapes could be generated [15], amongst them are the shapes which were very nearly constant.”
Quasi-Single Field Inflation and Non-Gaussianities (2009, methodology): “To study the leading order perturbations, we first present a simple intuitive approach [2] and then justify it using a rigorous method.”
Testing Inflation with Large Scale Structure: Connecting Hopes with Reality (2014, background): “A canonical example of the type is quasi-single field inflation [59, 60] and generalizations thereof [61–63].”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “Albeit unrelated to the orthogonal template, quasi-single-field models (Chen and Wang 2010) also give a k−1 scaling of the bias.”
General CMB and primordial bispectrum estimation: Mode expansion, map making, and measures of F NL (2009, background): “The large-angle solution (16) is an important benchmark with which to compare the shape of late-time CMB bispectra from other models bl1l2l3 (note the l −4 scaling) and, additionally, it has some further recent physical motivation [20].”
The effective field theory of multifield inflation (2010, background): “We do not study here the case, for example as treated in [48, 49], in which the additional fields have mass of order H, do not have scale invariant fluctuations, but nevertheless lead to physical effects because back-reacting on π.”
Primordial Features as Evidence for Inflation (2011, background): “Non-Gaussianities can be easily made non-scale-invariant if they are transferred from the isocurvature modes, for instance, when inflaton makes a non-constant turn in its trajectory in models of the type [16,17].”
Mass hierarchies and non-decoupling in multi-scalar field dynamics (2010, result): “We also extend recent results by [16, 21], that we recover in the right limits.”
Prospects for cosmological collider physics (2016, background): “[1] contains a heavy scalar field σ producing non-Gaussianities from a self-interaction σ3 vertex.”
Bootstrapping inflationary correlators in Mellin space (2019, background): “In the squeezed limit this exhibits the power-law/oscillatory behaviour expected from the presence of new particles [24, 25, 27, 29, 47, 48], with the angular dependence associated to the exchange of a spin-` field encoded in a Gegenbauer polynomial for general d.”
Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “This class of models is called quasi-single field inflation [207][98][159].”
Effective theories of single field inflation when heavy fields matter (2012, background): “In addition, the nature of the turn thus classified results in identifiably distinct contributions to observables: a strong turn for example, can reduce the speed of sound of the adiabatic mode, but for a constant radius of curvature, serves to only renormalize the power spectrum whilst generating e”
Effective field theory approach to quasi-single field inflation and effects of heavy fields (2012, methodology): “For this purpose, we first discuss the original model of quasi-single field inflation [29, 30], and then, we investigate the effects of heavy particles during inflation.”
On the statistics of biased tracers in the Effective Field Theory of Large Scale Structures (2015, background): “For example, in the local case, f loc NL, α = 0, for the equilateral, f equil NL [43], and orthogonal, f NL [44], cases, α = 2, 7 quasi-single field inflation [45, 46], gives 0 ≤ α ≤ 3/2.”