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Natural inflation, strong dynamics, and the role of generalized anomalies

Anber, Mohamed M.; Baker, Stephen

Natural inflation, strong dynamics, and the role of generalized anomalies Thumbnail


Stephen Baker


We revisit models of natural inflation and show that the single-field effective theory described by the potential V ( a ) ∼ cos a f breaks down as the inflaton a makes large-field excursions, even for values of f smaller than the Planck scale. To remedy the problem, we modify the potential in order to account for the heavy degrees of freedom (hadrons) that become intertwined with the light inflaton as the latter rolls down its potential. By embedding the low-energy degrees of freedom into an ultraviolet-complete gauge theory, we argue that the intertwining between the two scales can be explained as the result of a generalized mixed ’t Hooft anomaly between the discrete chiral symmetry and background fractional fluxes in the baryon number, color, and flavor directions. Further, we study the multifield inflation and show that it entertains rich dynamics. Inflating near the hilltop excites the hadrons and spoils the slow-roll parameters, in contradistinction with the expectations in the single-field inflation. Nevertheless, we identify a safe zone where inflation can proceed successfully. We determine the conditions under which the Universe inflates by at least 60 e -foldings and inflation leads to a power spectrum and tensor to scalar ratio that are consistent with the cosmic microwave background data.


Anber, M. M., & Baker, S. (2020). Natural inflation, strong dynamics, and the role of generalized anomalies. Physical Review D, 102(10), Article 103515.

Journal Article Type Article
Acceptance Date Oct 13, 2020
Online Publication Date Nov 13, 2020
Publication Date 2020
Deposit Date Oct 3, 2021
Publicly Available Date Oct 4, 2021
Journal Physical Review D
Print ISSN 2470-0010
Electronic ISSN 2470-0029
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 102
Issue 10
Article Number 103515


Published Journal Article (885 Kb)

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Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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