  We investigate the effects of a finite chemical potential $\mu$ in QCD viewed
as a disordered medium. In the quenched approximation, $A_4=i\mu$ induces a
complex electric Aharonov-Bohm effect that causes the diagonal contribution to
the quark return probability to vanish at $\mu=m_{\pi}/2$ (half the pion mass).
In two-color QCD, the weak-localization contribution to the quark return
probability remains unaffected causing a mutation in the spectral statistics.
In full QCD, the complex electric flux is screened and the light quarks are
shown to diffuse asymmetrically with a substantial decrease in the conductivity
along the `spatial' directions. Mean-field arguments suggest that a d=1
percolation transition may take place in the range $1.5\rho_0<\rho<3\rho_0$,
where $\rho_0$ is nuclear matter density.
