3 papers
hep-ph2026
Nonlinear physics of axion inflation
Oleksandr Sobol, Richard von Eckardstein, Elias Koch +3
An axion-like field coupled to an Abelian gauge field provides one of the simplest inflationary models that is free from the eta problem and possesses an efficient reheating mechan…
astro-ph.CO2025
Gravitational waves from axion inflation in the gradient expansion formalism. Part II. Fermionic axion inflation
Richard von Eckardstein, Kai Schmitz, Oleksandr Sobol
Axion inflation represents an intriguing source of gravitational waves (GWs) from the early Universe. In a companion paper, arXiv:2508.00798, we previously leveraged the gradient e…
astro-ph.CO2025
Gravitational waves from axion inflation in the gradient expansion formalism. Part I. Pure axion inflation
Richard von Eckardstein, Kai Schmitz, Oleksandr Sobol
Axion inflation is a well-motivated model of cosmic inflation with a rich phenomenology. The abundant production of gauge fields during axion inflation notably sources a stochastic…