Unified description of the dynamics of quintessential scalar fields

Abstract

Using the dynamical system approach, we describe the general dynamicsof cosmological scalar fields in terms of critical points andheteroclinic lines. It is found that critical points describe theinitial and final states of the scalar field dynamics, but thatheteroclinic lines give a more complete description of theevolution in between the critical points. In particular, theheteroclinic line that departs from the (saddle) critical point ofperfect fluid-domination is the representative path in phase space ofquintessence fields that may be viable dark energy candidates. We alsodiscuss the attractor properties of the heteroclinic lines, and theirimportance for the description of thawing and freezing fields.