Understanding large scale CMB anomalies with the generalized non-minimal derivative coupling during inflation

Fuente: arXiv
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Auteurs principaux: Tiwari, Yashi, Bhaumik, Nilanjandev, Jain, Rajeev Kumar
Format: Preprint
Publié: 2022
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author Tiwari, Yashi
Bhaumik, Nilanjandev
Jain, Rajeev Kumar
author_facet Tiwari, Yashi
Bhaumik, Nilanjandev
Jain, Rajeev Kumar
contents We study the observational implications of a class of inflationary models wherein the inflaton is coupled to the Einstein tensor through a generalized non-minimal derivative coupling (GNMDC). In particular, we explore whether these models can generate suitable features in the primordial spectrum of curvature perturbations as a possible explanation for the large-scale anomalies associated with the angular power spectrum of CMB temperature anisotropies. We derive model-independent constraints on the GNMDC function for such a scenario, considering both the scalar and tensor perturbations. We modify CosmoMC to accommodate our GNMDC framework and investigate different classes of inflationary models using a fully consistent numerical approach. We find that the hilltop-quartic model with a specific choice of the GNMDC function provides a considerable improvement over the best-fit reference $Λ$CDM model with a nearly scale-invariant power spectrum. While the large-scale structure observations should be able to provide independent constraints, future CMB experiments, such as CMB-S4 and CMB-Bharat, are expected to constrain further the parameter space of such beyond canonical single-field inflationary models.
format Preprint
id arxiv_https___arxiv_org_abs_2206_13320
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Understanding large scale CMB anomalies with the generalized non-minimal derivative coupling during inflation
Tiwari, Yashi
Bhaumik, Nilanjandev
Jain, Rajeev Kumar
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
We study the observational implications of a class of inflationary models wherein the inflaton is coupled to the Einstein tensor through a generalized non-minimal derivative coupling (GNMDC). In particular, we explore whether these models can generate suitable features in the primordial spectrum of curvature perturbations as a possible explanation for the large-scale anomalies associated with the angular power spectrum of CMB temperature anisotropies. We derive model-independent constraints on the GNMDC function for such a scenario, considering both the scalar and tensor perturbations. We modify CosmoMC to accommodate our GNMDC framework and investigate different classes of inflationary models using a fully consistent numerical approach. We find that the hilltop-quartic model with a specific choice of the GNMDC function provides a considerable improvement over the best-fit reference $Λ$CDM model with a nearly scale-invariant power spectrum. While the large-scale structure observations should be able to provide independent constraints, future CMB experiments, such as CMB-S4 and CMB-Bharat, are expected to constrain further the parameter space of such beyond canonical single-field inflationary models.
title Understanding large scale CMB anomalies with the generalized non-minimal derivative coupling during inflation
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2206.13320