Stability of the 3-form field during inflation

Understand

We consider the minimally coupled 3-form field which has been considered as a candidate to realize inflation.

• We have studied the conditions to avoid ghosts and Laplacian instabilities and found that some classes of potentials, e.g.
• the Mexican-hat one, will in general be unstable.
• We then propose other classes of potentials which are instead free from any instability, drive a long-enough slow-roll regime followed by an oscillatory epoch, and as a consequence, can provide successful inflation.