  The relationship between mesonic correlations and quantum condensates in the
quark matter phase diagram is explored within a quantum field theoretical
approach of the Nambu and Jona-Lasinio (NJL) type. Mean-field values in the
scalar meson and diquark channels are order parameters signalling the
occurrence of quark condensates, entailing chiral symmetry breaking (chi SB)
and color superconductivity (2SC) in quark matter. We investigate the spectral
properties of scalar and pseudoscalar meson excitations in the phase diagram in
Gaussian approximation and show that outside the chi SB region where the pion
is a zero-width bound state, there are two regions where it can be considered
as a quasi-bound state with a lifetime exceeding that of a typical heavy-ion
collision fireball: (A) the high-temperature chi SB crossover region at low
densities and (B) the high-density color superconducting phase at temperatures
below 100 MeV.
