Interaction between Dark Matter and Dark Energy and the Cosmological Coincidence Problem

Figure 3

(a) The phase plane for critical (for minimal case) with and . The critical points are stable nodes (sinks) so that the quintessence dominated solution is the late time attractor. The critical points and are saddle points, but , fixed points are repeller nodes. All the phase space trajectories diverge from the unstable point and converge towards the attractor. (b) The phase plane for the critical point (for nonminimal case) with , and . The critical point is a stable node (a sink) so that the quintessence dominated solution is a future attractor.

(a)

(b)