SIMPLE ANSATZ FOR THE LATTICE FERMION DETERMINANT

An ansatz for the fermion vacuum functional on a lattice is proposed. It is proved to reproduce correct continuum limit for convergent diagr ams of any finite order in smooth external fields, as well as consiste nt chiral anomalies, and ensures gauge invariance of the absolute valu e of the functional at any lattice spacing. The ansatz corresponds to a certain nonlocal fermion action having global chiral invariance. Pro blems caused by non-smooth gauge fields are discussed. (C) 1997 Publis hed by Elsevier Science B.V.