High-frequency Graviton from Inflaton Oscillation

Understand

We point out that there is a high-frequency tail of the stochastic inflationary gravitational wave background that scales as $f^{-1/2}$ with frequency $f$.

• This contribution comes from the graviton vacuum fluctuation amplified by the inflaton coherent oscillation during the reheating stage.
• It contains information on inflaton properties such as the inflaton mass as well as the thermal history of the early Universe.