Some Conceptual Issues in Finite Density QCD

While a mature subject by itself, finite density quantum chromo dynamics (QCD), and indeed any finite density field theory, turns out to have some hidden issues in form of spurious chemical potential-dependent divergences. These were first encountered, and fixed, in the lattice formulation in a way which, however, affects the modern lattice computations of interesting physical quantities. We point out that exact chiral fermions need an alternate way to handle them, which turns out better for other fermions as well.