Möbius Fermions

We introduce a new domain wall operator that represents a full (real) Möbius transformation of a given nonchiral Dirac kernel. Shamir's and Chiu/Boriçi's domain wall fermions are special cases of this new class. By tuning the parameters of the Möbius operator and by introducing a new Red/Black preconditioning, we are able to reduce the computational effort substantially.