Preheating with the Brakes On: The Effects of a Speed Limit

Understand

We study preheating in models where the inflaton has a non-canonical kinetic term, containing powers of the usual kinetic energy.

• The inflaton field oscillating about its potential minimum acts as a driving force for particle production through parametric resonance.
• Non-canonical kinetic terms can impose a speed limit on the motion of the inflaton, modifying the oscillating inflaton profile.
• This has two important effects: it turns a smooth sinusoidal profile into a sharp saw-tooth, enhancing resonance, and it lengthens the period of oscillations, suppressing resonance.