Is the NANOGrav detection evidence of resonant particle creation during inflation?

Understand

We show that the recently reported cosmic gravitational wave background by the NANOGrav 15-year collaboration may be the result of resonant particle creation during inflation.

• For the appropriate amplitude and particle mass an enhancement of the primordial scalar power spectrum could induce Secondary Induced Gravitational Waves (SIGW) which will appear on a scale corresponding to the frequency of the NANOGrav detection.
• Since the resonant creation will have an effect comparable to that of a delta function increment as studied by the NANOGrav 15-year collaboration, our study indicates that the low-frequency Pulsar Timing Array (PTA) data could reveal the aspects of the physics during inflation through the detection of a cosmic background of Gravitational Waves (GW).