Warm inflation with non-comoving scalar field and radiation fluid

Understand

We consider a warm inflationary scenario in which the two dominant matter components present in the early Universe, the scalar field, and the radiation fluid, evolve with different four-velocities.

• This cosmological system is mathematically equivalent to a single anisotropic fluid, evolving with a four-velocity that is a function of the two independent fluid four-velocities.
• Due to the presence of the anisotropic physical parameters, the overall cosmological evolution is also anisotropic.
• We derive the gravitational field equations of the noncomoving scalar field-radiation mixture for a Bianchi type I geometry.