  The idea that the explicit breaking of scale invariance by the trace anomaly
of QCD can be rephrased as a spontaneous breaking has been recently exploited
to capture the low-energy strong interaction dynamics of dense (and also hot)
matter in terms of two dilaton fields, the "soft" (chi_s) and the "hard"
(chi_h) fields, in the frame work of the hidden local gauge symmetry. In the
Freund-Nambu model, the spontaneous symmetry breaking of scale symmetry is
induced by an explicitly breaking term, while the spontaneous symmetry breaking
is possible in the flat potential model which is scale symmetric. We discuss
the interplay of the soft and hard dilatons using the spontaneously broken
scale symmetry schemes and uncover a novel structure of dense matter hitherto
unexplored.
