Constraining the bispectrum from bouncing cosmologies with Planck

Abstract

Bouncing models of cosmology, as they arise e.g. in loop quantum cosmology, can be followed by an inflationary phase and generate close-to-scale-invariant fluctuation spectra as observed in the Cosmic Microwave Background (CMB). However, they are typically not Gaussian and also generate a bispectrum. These models can help to mitigate the large-scale anomalies of the CMB by considering substantial non-Gaussianities on very large scales, which decay exponentially on sub-horizon scales. It was therefore thought that this non-Gaussianity would not be visible in observations, which can only probe sub-horizon scales. In this letter we show that bouncing models with parameters such that they can significantly mitigate the large-scale anomalies of the CMB are excluded by the Planck data with high significance of, depending on the specific model, $5.4$, $6.4$ or $14$ standard deviations.

arXiv comment5 pages, 1 figure

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• Observations in Quantum Cosmology
• Loop quantum cosmology: relation between theory and observations
• Cuscuton Bounce Beyond the Linear Regime: Bispectrum and Strong Coupling Constraints
• Estimation of imprints of the bounce in loop quantum cosmology on the bispectra of cosmic microwave background
• Constraints on primordial non-Gaussianity from Planck PR4 data
• Power Suppression and Lensing Anomaly -- A phenomenological investigation
• Introdução à Cosmologia Quântica