Holographic hessence models

We discuss the evolution of holographic hessence model, which satisfies the holographic principle and can naturally realize the equation of state crossing -1. By discussing the evolution of the models in the w-w' plane, we find that, if c >= 1, w(he) >= -1 and V < 0 keep for all time, which are quintessence-like. However, if c < -1, which mildly favors the current observations, whe evolves from w(he) > -1 to w(he) < - 1, and the potential is a nonmonotonic function. In the earlier time, the potential must be rolled down, and then be climbed up. Considered the current constraint on the parameter c, we reconstruct the potential of the holographic hessence model. (C) 2007 Elsevier B.V All rights reserved.