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 = m_π/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 1.5ρ₀ < p < 3ρ₀, where ρ₀ is nuclear matter density.