Non-Gaussian enhancements of galactic halo correlations in quasi-single field inflation

We study a simple extension of quasi-single field inflation in which the inflaton interacts with multiple extra massive scalars known as isocurvatons. Due to the breaking of time translational invariance by the inflaton background, the theory includes kinetic mixings among the inflaton and isocurvatons. These mixings give rise to novel new features in the primordial non-Gaussianities of the scalar curvature perturbation. A noteworthy feature is the amplitude of the squeezed bispectrum can grow nearly as (k s /k l ) −3 while oscillating as cos γ log(k s /k l ), where k s /k l is the ratio of the lengths of the short and long wavevectors. Observation of such a shape would provide evidence for the existence of multiple isocurvatons during inflation. In addition, we consider the effects of these non-Gaussianities on large-scale structure.1 Large non-Gaussianities can also be achieved in more complicated single field models, see for example [6,7].

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“…which is close to the shape function of the single-isocurvaton QSFI originally considered by Chen and Wang in the limit µ 1 , m 11 H [8,15]. Fig.…”

Section: A Bispectrumsupporting

confidence: 85%

New shapes of primordial non-Gaussianity from quasi-single field inflation with multiple isocurvatons

McAneny

Ridgway

2019

Phys. Rev. D

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“…Notice that, as long as we are constraining non-Gaussianity using the halo power spectrum only, any information on the angle between k s and k is lost. One needs to look at the bispectrum [272][273][274][275][276][277][278][279][280][281][282][283][284][285][286][287] or, alternatively, to galaxy shapes [20,21] and intrinsic alignments [22] to be sensitive to it.…”

Section: The Squeezed Limit Of the Primordial Bispectrummentioning

confidence: 99%

“…Differently than for the power spectrum, where only the squeezed configurations contribute to the signature, the full shape of non-Gaussianity can be probed in the bispectrum. Theoretical and numerical work has been also making progress in this direction in the last decade [272][273][274][275][276][277][278][279][280][281][282][283][284][285][286][287]364]. The main challenges to overcome with the galaxy bispectrum is the fact that gravitational non-linearities developed at late times dominate over primordial ones.…”

Section: Observational Prospectsmentioning

confidence: 99%

The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

Biagetti

2019

Galaxies

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The understanding of the primordial mechanism that seeded the cosmic structures we observe today in the sky is one of the major goals in cosmology. The leading paradigm for such a mechanism is provided by the inflationary scenario, a period of violent accelerated expansion in the very early stages of evolution of the universe. While our current knowledge of the physics of inflation is limited to phenomenological models which fit observations, an exquisite understanding of the particle content and interactions taking place during inflation would provide breakthroughs in our understanding of fundamental physics at high energies. In this review, we summarize recent theoretical progress in the modeling of the imprint of primordial interactions in the large-scale structures of the universe. We focus specifically on the effects of such interactions on the statistical distribution of dark-matter halos, providing a consistent treatment of the steps required to connect the correlations generated among fields during inflation all the way to the late-time correlations of halos.

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“…A detection of a boosted collapsed four-point function [14] would indicate the role of more than one source in generating the curvature perturbations. The effect of such four-point functions on the large-scale structure clustering has been extensively studied [15][16][17][18][19][20].…”

mentioning

confidence: 99%

Super-CMB fluctuations and the Hubble tension

Adhikari

Huterer

2020

Physics of the Dark Universe

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We study the covariance in the angular power spectrum estimates of CMB fluctuations when the primordial fluctuations are non-Gaussian. The non-Gaussian covariance comes from a nonzero connected four-point correlation function -or the trispectrum in Fourier space -and can be large when long-wavelength (super-CMB) modes are strongly coupled to short-wavelength modes. The effect of such non-Gaussian covariance can be modeled through additional freedom in the theoretical CMB angular power spectrum and can lead to different inferred values of the standard cosmological parameters relative to those in ΛCDM. Taking the collapsed limit of the primordial trispectrum in the quasi-single field inflation model as an example, we study how the six standard ΛCDM parameters shift when two additional parameters describing the trispectrum are allowed. We find that the combination of Planck temperature data along with type Ia supernovae from Panstarrs and the distance-ladder measurement of the Hubble constant shows strong evidence for a primordial trispectrum-induced non-Gaussian covariance, with a likelihood improvement of ∆χ 2 ≈ −15 relative to ΛCDM. The improvement is driven by Planck data's preference for a higher lensing amplitude, which leads to an upward shift of the Planck-inferred Hubble constant.

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Non-Gaussian enhancements of galactic halo correlations in quasi-single field inflation

Cited by 59 publications

References 49 publications

New shapes of primordial non-Gaussianity from quasi-single field inflation with multiple isocurvatons

New shapes of primordial non-Gaussianity from quasi-single field inflation with multiple isocurvatons

The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

Super-CMB fluctuations and the Hubble tension

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