Fixed Point Actions for Wilson Fermions

Abstract

Iterating renormalization group transformations for lattice fermions the Wilson action is driven to fixed points of the renormalization group. A line of fixed points is found and the fixed point actions are computed analytically. They are local and may be used to improve scaling in lattice QCD. The action at the line's endpoint is chirally invariant and still has no fermion doubling. The Nielsen-Ninomiya theorem is evaded because in this case the fixed point action is nonlocal. The use of this action for a construction of lattice chiral fermions is discussed.