Noether Symmetry Approach in "Cosmic Triad" Vector Field Scenario
  To realize the accelerations in the early and late periods of our universe,
we need to specify potentials for the dominant fields. In this paper, by using
the Noether symmetry approach, we try to find suitable potentials in the
"cosmic triad" vector field scenario. Because the equation of state parameter
of dark energy has been constrained in the range of $-1.21\leq \omega\leq
-0.89$ by observations, we derive the Noether conditions for the vector field
in quintessence, phantom and quintom models, respectively. In the first two
cases, constant potential solutions have been obtained. What is more, a fast
decaying point-like solution with power-law potential is also found for the
vector field in quintessence model. For the quintom case, we find an
interesting constraint $\tilde{C}V_{p}'=-CV_{q}'$ on the field potentials,
where $C$ and $\tilde{C}$ are constants related to the Noether symmetry.
