Inflation with conformally coupled scaler field

In a Robertson-Walker geometry conformally coupled to a scalar field with inflation potential V(phi) = M(4) - (1/4)lambda phi(4), we investigate the classical evolution of a universe. The exact solutions in the model have been found. It is shown that in the region where the value of the phi field is 0 < phi < phi(max), (phi(max) is the solution of V(phi) = 0), there is inflation. This model can lead to successful inflation with lambda similar to 10(-9), rather than 10(-13) as previously reported.