Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
CMB Power Asymmetry from Non-Gaussian Modulation
2 Pith papers cite this work, alongside 70 external citations. Polarity classification is still indexing.
abstract
Non-Gaussianity in the inflationary perturbations can couple observable scales to modes of much longer wavelength (even superhorizon), leaving as a signature a large-angle modulation of the observed cosmic microwave background (CMB) power spectrum. This provides an alternative origin for a power asymmetry which is otherwise often ascribed to a breaking of statistical isotropy. The non-Gaussian modulation effect can be significant even for typical ~10^{-5} perturbations, while respecting current constraints on non-Gaussianity, if the squeezed limit of the bispectrum is sufficiently infrared divergent. Just such a strongly infrared-divergent bispectrum has been claimed for inflation models with a non-Bunch-Davies initial state, for instance. Upper limits on the observed CMB power asymmetry place stringent constraints on the duration of inflation in such models.
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Forecasts show that future 21 cm surveys can deliver moderate constraints on the scale-dependent growth index and HI bias in viable f(R) models.
citing papers explorer
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Searching for primordial features with radio surveys: synergy between the power spectrum and bispectrum
Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
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Constraining Scale-Dependent Growth in $f(R)$ Gravity with Future 21 cm Surveys
Forecasts show that future 21 cm surveys can deliver moderate constraints on the scale-dependent growth index and HI bias in viable f(R) models.