Currents, chemical potential and boundary conditions in lattice QCD
  A connection between the operator fermionic currents $\hatJ$ and corresponding `Grassmannian' currents $J$ in the functional integral formalism is studied. The QCD action with non--zero chemical potential $\mu$ is derived. A connection between the fermionic Fock space and boundary conditions along the forth direction is discussed. 
V.K. Mitrjushkin (JINR, Dubna)