We discuss the possibility that in finite density QCD an anisotropic phase is
realized. This case might arise for quarks with different chemical potential
and/or different masses. In this phase crystalline structures may be formed. We
consider this possibility and we describe, in the context of an effective
lagrangian, the corresponding phonons as the Nambu-Goldstone bosons associated
to the breaking of the space symmetries.Comment: LaTex,20 pages, 6 figures. Talk at the International Workshop on QCD:
QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614). Change in
the CERN preprint numbe
