Domain-wall fermion with R5R5 symmetry

We present the domain-wall fermion operator which is reflection symmetric in the fifth dimension, with the approximate sign function S(H)S(H) of the effective 4-dimensional Dirac operator satisfying the bound |1−S(λ)|≤2dZ|1−S(λ)|≤2dZ for λ2∈[λmin2,λmax2], where dZdZ is the maximum deviation |1−xRZ(x)|max of the Zolotarev optimal rational polynomial RZ(x)RZ(x) of 1/x for x∈[1,λmax2/λmin2], with degrees (n−1,n)(n−1,n) for Ns=2nNs=2n, and (n,n)(n,n) for Ns=2n+1Ns=2n+1.