430694.fig.0010a
(a)
430694.fig.0010b
(b)
430694.fig.0010c
(c)
430694.fig.0010d
(d)
Figure 10: Cosmological evolution of , , , , , , with the scale factor. Top: the case and corresponds to a “double inflation.” The scenario is pathological in many respects: singularity in the scalar field velocity (see (a)) while the scalar field EoS is imaginary. Also (see (b), the axis is logarithmic): and there are periods for which and . Bottom: the case and . The model is well behaved but does not accelerate the expansion, that is, as in the John alone model. The universe is actually in a super stiff regime and hence in a highly decelerating phase.