Chiral disorder and QCD at finite chemical potential

We investigate the effects of a finite chemical potential μ in QCD viewed as a disordered medium. In the quenched approximation, A4=iμ induces a complex electric Aharonov-Bohm effect that causes the diagonal contribution to the quark return probability to vanish at μ=mπ/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 `spatialʹ directions. Mean-field arguments suggest that a d=1 percolation transition may take place in the range 1.5ρ0<ρ<3ρ0, where ρ0 is nuclear matter density.