Gravitational waves from p-form inflation

Understand

Recently it was shown that an inflationary background can be realized by any $p$-form field non-minimally coupled to gravity.

• In this paper, we study gravitational waves generated during p-form inflation.
• Even though the background evolution is identical to that in conventional scalar field inflation, the behavior of gravitational waves is different in p-form inflation.
• In particular, we find that the propagation speed of gravitational waves differs from unity in 2- and 3-form inflationary models.