Can the quintessence be a complex scalar field?

In light of the recent observations of type Ia supernovae suggesting an accelerating expansion of the Universe, we wish in this Letter to point out the possibility of using a complex scalar field as the quintessence to account for the acceleration. In particular, we extend the idea of Huterer and Turner in deriving the reconstruction equations for the complex quintessence, showing the feasibility of making use of a complex scalar field (instead of a real scalar field) while maintaining the uniqueness feature of the reconstruction for two possible situations, respectively. We discuss very briefly how future observations may help to distinguish the different quintessence scenarios, including the scenario with a positive cosmological constant. (C) 2001 Elsevier Science B.V. All rights reserved.