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The shape of primordial non-Gaussianity and the CMB bispectrum

2 Pith papers cite this work. Polarity classification is still indexing.

2 Pith papers citing it
abstract

We present a set of formalisms for comparing, evolving and constraining primordial non-Gaussian models through the CMB bispectrum. We describe improved methods for efficient computation of the full CMB bispectrum for any general (non-separable) primordial bispectrum, incorporating a flat sky approximation and a new cubic interpolation. We review all the primordial non-Gaussian models in the present literature and calculate the CMB bispectrum up to l <2000 for each different model. This allows us to determine the observational independence of these models by calculating the cross-correlation of their CMB bispectra. We are able to identify several distinct classes of primordial shapes - including equilateral, local, warm, flat and feature (non-scale invariant) - which should be distinguishable given a significant detection of CMB non-Gaussianity. We demonstrate that a simple shape correlator provides a fast and reliable method for determining whether or not CMB shapes are well correlated. We use an eigenmode decomposition of the primordial shape to characterise and understand model independence. Finally, we advocate a standardised normalisation method for $f_{NL}$ based on the shape autocorrelator, so that observational limits and errors can be consistently compared for different models.

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hep-th 2

years

2026 1 2025 1

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UNVERDICTED 2

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representative citing papers

Inflation with vector fields revisited: non-Gaussianities

hep-th · 2026-05-27 · unverdicted · novelty 5.0

In kinetically coupled vector inflation, the bispectrum in the large-h regime exhibits competing local and flattened non-Gaussian signals with distinct h scalings that distinguish vector-supported dynamics.

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Showing 2 of 2 citing papers.

  • Inflation with vector fields revisited: non-Gaussianities hep-th · 2026-05-27 · unverdicted · none · ref 49 · internal anchor

    In kinetically coupled vector inflation, the bispectrum in the large-h regime exhibits competing local and flattened non-Gaussian signals with distinct h scalings that distinguish vector-supported dynamics.

  • A Match Made in Heaven: Linking Observables in Inflationary Cosmology hep-th · 2025-05-21 · unverdicted · none · ref 110 · internal anchor

    In dynamical Chern-Simons inflation the parity-odd trispectrum is a double copy of the mixed bispectrum and parity-odd power spectrum via a prior factorization formula.