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arXiv · 2510.02828

Suppression of scalar perturbations due to a heavy axion

Kai-Ge Zhang·Jian-Feng He·Chengjie Fu·Zong-Kuan Guo
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Abstract

A fast-rolling axion can transfer its kinetic energy to gauge fields via the Chern-Simons coupling, leading to copious production of gauge quanta during inflation. The amplified gauge fields act as a source for both scalar and tensor perturbations. In this work, we propose a mechanism for suppressing scalar perturbations while sourcing strong tensor perturbations. We present an implementation of such a mechanism, demonstrating that sourced tensor perturbations are expected to be detected by upcoming next-generation CMB experiments.

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Kai-Ge Zhang, Jian-Feng He, Chengjie Fu, Zong-Kuan Guo. 2025-10-03. Suppression of scalar perturbations due to a heavy axion. https://doi.org/10.1103/4wtv-xdwj

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