  This note discusses the Wigner function representation from the standpoint of
establishing a holography-like correspondence between the descriptions of a
generic quantum system in the phase space ('bulk') picture versus its spacetime
('boundary') counterpart. Under certain circumstances the former might reduce
to the classical dynamics of a local metric-like variable while the latter
takes on the form of some bosonized collective field hydrodynamics. This
generic pseudo-holographic duality neither relies on any particular symmetry of
the system in question, nor does it require any connection to an underlying
'string theory', as in the various 'ad hoc' scenarios of applied holography.
