Crossing w = − 1 by a single scalar on a Dvali - Gabadadze - Porrati brane

Recent type Ia supernovae data seem to favor a dark energy model whose equation of state w(z) crosses −1, which is a much more amazing problem than the acceleration of the universe. Either the case that w(z) evolves from above −1 to below −1 or the case that w(z) runs from below −1 to above −1, sometimes dubbed quintom A and quintom B, respectively, is consistent with present data. In this paper we show that it is possible to realize the behaviour of quintom A or quintom B by only a single scalar field in frame of Dvali-Gabadadze-Porrati braneworld. At the same time we prove that there does not exist scaling solution in a universe with dust.