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Understanding large scale CMB anomalies with the generalized nonminimal derivative coupling during inflation

Tiwari, Y and Bhaumik, N and Jain, RK (2023) Understanding large scale CMB anomalies with the generalized nonminimal derivative coupling during inflation. In: Physical Review D, 107 (10).

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Official URL: https://doi.org/10.1103/PhysRevD.107.103513


We study the observational implications of a class of inflationary models wherein the inflaton is coupled to the Einstein tensor through a generalized nonminimal 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 ΛCDM 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.

Item Type: Journal Article
Publication: Physical Review D
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the publisher.
Department/Centre: Division of Physical & Mathematical Sciences > Joint Astronomy Programme
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 27 Jun 2023 05:24
Last Modified: 27 Jun 2023 05:24
URI: https://eprints.iisc.ac.in/id/eprint/82033

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