The Quintom scenario (derived from the words quintessence and phantom, as in phantom energy) is a hypothetical scenario involving dark energy.
In this scenario, the equation of state crosses a boundary value for the cosmological constant (
A no-go theorem shows that this scenario requires at least two degrees of freedom for dark energy models.
If this scenario exists, it may indicate how the universe avoids Big Bangs, Big Rips, and other time-like singularities.
The Quintom Scenario was applied in 2008 to a model of inflationary cosmology without a Big Bang singularity. It was also applied in 2007 to a Big Bounce model of the universe.