13 papers
Axion isocurvature and the model-building problem of low-scale inflation
Sarunas Verner
The pre-inflationary QCD axion is often said to require low-scale inflation. We derive a general isocurvature bound for a light axion with a scale-invariant spectrum, treating its…
Reheating in No-Scale Models of Inflation
Ignatios Antoniadis, John Ellis, Dimitri V. Nanopoulos +2
Analogously to the suppression of inflaton decays into conformally-coupled scalar fields in the original Starobinsky model of inflation, inflaton decays to Standard Model…
Cosmological gravitational particle production in multifield inflation
Edward W. Kolb, Sarunas Verner, Jingyuan Wang
We study cosmological gravitational particle production (CGPP) of dark matter in two-field inflationary backgrounds with both flat and curved field-space geometries. As a concrete…
Gravitational Waves from Matter Perturbations of Spectator Scalar Fields
Marcos A. G. Garcia, Angel Garcia-Vega, Sarunas Verner
We compute the stochastic gravitational wave background sourced at second order by a spectator scalar field coupled to the inflaton through a portal interaction $ÏÏ^2Ï…
Gravitational Production of Massive Spin-2 Particles During Reheating
Sarunas Verner
We study the minimal gravitational portal for a massive spin-2 dark matter candidate produced during perturbative reheating. The dark sector couples to the visible secto…
Gravitational Waves from Isocurvature Perturbations of Spectator Scalar Fields
Marcos A. G. Garcia, Sarunas Verner
We present a mechanism for gravitational wave (GW) production from isocurvature perturbations in spectator scalar fields during inflation. These energetically subdominant fields de…