The Quintessence Potential: Need for Features and Tracking? – Martin Sahlen

Date: Tue. November 28th, 2006, 11:30 am-12:30 pm
Location: Rockefeller 221

We reconstruct the potential of a quintessence field from current observational data, including new supernova data, plus information from the cosmic microwave background and from baryon acoustic oscillations. We model the potential using Pade approximant expansions as well as Taylor series, and use observations to assess the viability of the tracker hypothesis. Present data provide some insights into the shape of a presumptive quintessence potential, but also strengthen the model selection preference for the cosmological constant over evolving models. They also show some signs, though inconclusive, of favouring tracker models over non-tracker models under our assumptions.