Dynamics of Dirac-Born-Infeld dark energy interacting with dark matter
  We study the dynamics of Dirac-Born-Infeld (DBI) dark energy interacting with
dark matter. The DBI dark energy model considered here has a scalar field with
a nonstandard kinetic energy term, and has potential and brane tension that are
power-law functions. The new feature considered here is an interaction between
the DBI dark energy and dark matter through a phenomenological interaction
between the DBI scalar field and the dark matter fluid. We analyze two
different types of interactions between the DBI scalar field and the dark
matter fluid. In particular we study the phase-space diagrams of and look for
critical points of the phase space that are both stable and lead to
accelerated, late-time expansion. In general we find that the interaction
between the two dark components does not appear to give rise to late-time
accelerated expansion. However, the interaction can make the critical points in
the phase space of the system stable. Whether such stabilization occurs or not
depends on the form of the interaction between the two dark components.
