Cosmological Dark sector from a Mimetic-Metric-Torsion perspective
  We generalize the basic theory of mimetic gravity by extending its purview to
the general metric-compatible geometries that admit torsion, in addition to
curvature. This essentially implies reinstating the mimetic principle of
isolating the conformal degree of freedom of gravity in presence of torsion, by
parametrizing both the physical metric and torsion in terms of the scalar
`mimetic' field and the metric and torsion of a fiducial space. We assert the
requisite torsion parametrization from an inspection of the fiducial space
Cartan transformation which, together with the conformal transformation of the
fiducial metric, preserve the physical metric and torsion. In formulating the
scalar-tensor equivalent Lagrangian, we consider an explicit contact coupling
of the mimetic field with torsion, so that the former can manifest itself
geometrically as the source of a torsion mode, and most importantly, give rise
to a viable `dark universe' picture from a mimicry of an evolving dust-like
cosmological fluid with a non-zero pressure. A further consideration of higher
derivatives of the mimetic field in the Lagrangian leads to physical bounds on
the mimetic-torsion coupling strength, which we determine explicitly.
