Two-field disformal transformation and mimetic cosmology

Understand

We extend the disformal transformation to models with two scalar fields and look at its singular limit.

• Solving the eigentensor equation for the Jacobian of the transformation of the metrics we find the two-field extension of the mimetic scenario in the singular conformal limit.
• At the background level the setup mimics the roles of dark matter cosmology.
• We decompose the perturbations into the adiabatic and entropy modes in which the adiabatic perturbation is tangential to the classical trajectory while the entropy mode is perpendicular to it.