Graviton Creation by Small Scale Factor Oscillations in an Expanding Universe

Understand

We treat quantum creation of gravitons by small scale factor oscillations around the average of an expanding universe.

• Such oscillations can arise in standard general relativity due to oscillations of a homogeneous, minimally coupled scalar field.
• They can also arise in modified gravity theories with a term proportional to the square of the Ricci scalar in the gravitational action.
• The graviton wave equation is different in the two cases, leading to somewhat different creation rates.