Anything with negative pressure, the general theory of relativity dictates, would have a gravitationally repulsive force. For quintessence, the quantum field would have a very long wavelength, about the size of the universe. So for now, potential energy and negative pressure dominates. Hence, quintessence is a repulsive force This can change, Steinhardt says. Quintessence interacts with matter and evolves over time.
Quintessence can also decay into new forms of hot matter or radiation.
So we are not necessarily doomed to a universe that expands forever, stretching every atom from here to infinity. Sounds nice, but not everyone is sold. I admire the architecture, but I would not want to move in just yet. Indeed, at the Texas Symposium, polite arguments over quintessence stretched well into the next talk. Some suggested that the nature of dark energy would become clear with a better understanding of gravity and gravitational waves.