Modified Brans-Dicke cosmology with matter-scalar field interaction

Understand

We discuss the cosmological implications of an extended Brans-Dicke theory presented recently, in which there is an energy exchange between the scalar field and ordinary matter, determined by the theory.

• A new mass scale is generated in the theory which modifies the Friedmann equations with field-dependent corrected kinetic terms.
• In a radiation universe the general solutions are found and there are branches with complete removal of the initial singularity, while at the same time a transient accelerating period can occur within deceleration.
• Entropy production is also possible in the early universe.