4 papers
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…
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…
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…
On the Schwinger effect during axion inflation
Richard von Eckardstein, Kai Schmitz, Oleksandr Sobol
Pair-creation of charged particles in a strong gauge-field background - the renowned Schwinger effect - can strongly alter the efficiency of gauge-field production during axion inf…