Nonminimal coupling, quartic potential and perfect fluid cosmologies

摘要: Perfect-fluid matter, satisfying the equation of state p=(γ−1)ρ, is considered in cosmologies where geometry nonminimally coupled with a scalar field ɸ and potential λɸ4+Λ. Exact solutions are found when γ constant describing ordinary forms matter (γ=1, dust, γ=4/3, radiation, γ=2, stiff γ=0, matter) discussion done order to recover Einstein gravity Newton observed today. The various can be classified according different values γ, λ Λ.