  A highlight of Fermi-liquid phenomenology, as explored in neutral $^3$He, is
the observation that in the collisionless regime shear stress propagates as if
one is dealing with the transverse phonon of a solid. The existence of this
$"$transverse zero sound$"$ requires that the quasiparticle mass enhancement
exceeds a critical value. Could such a propagating shear stress also exist in
strongly correlated electron systems? Despite some noticeable differences with
the neutral case in the Galilean continuum, we arrive at the verdict that
transverse zero sound should be generic. We present an experimental setup that
should be exquisitely sensitive in this regard: the transmission of terahertz
radiation through a thin slab of heavy-fermion material will be strongly
enhanced at low temperature and accompanied by giant oscillations, which
reflect the interference between light itself and the $"$material photon$"$
being the actual manifestation of transverse zero sound in the charged Fermi
liquid.
