Anomalies at finite density and chiral fermions

Abstract

Using perturbation theory in the Euclidean (imaginary time) formalism as well as the nonperturbative Fujikawa method, we verify that the chiral anomaly equation remains unaffected in the presence of nonzero chemical potential, μ. We extend our considerations to fermions with exact chiral symmetry on the lattice and discuss the consequences for the recent Bloch-Wettig proposal for the Dirac operator at finite chemical potential. We propose a new simpler method of incorporating μ and compare it with the Bloch-Wettig idea.