A new extended quintessence

Understand

Extended quintessence is obtained by coupling a normal scalar field to the Ricci scalar defined in the metric formalism.

• In this paper, we propose a new extended quintessence dark energy by introducing a non-minimal coupling between the quintessence and gravity, but with the Ricci scalar given from the Palatini formalism rather than the metric one.
• We find that the equation of state of the new extended quintessence can cross the phantom divide line, and moreover, it oscillates around the -1 line.
• We also show that the universe driven by the new extended quintessence will enter a dark energy dominated de Sitter phase in the future.