Brillouin improvement for Wilson fermions

Abstract

We present a parameter-free Wilson-type lattice Dirac operator with an 81-point stencil for the covariant derivative and the Laplacian, which attempts to minimize the breaking of rotational symmetry near the boundary of the Brillouin zone. The usefulness of this ''Brillouin operator'' in practical applications is explored by studying the scaling of pseudoscalar decay constants in quenched QCD, with rather good results in the physical charm region. We also investigate the suitability of this operator as a kernel to the overlap procedure. Here, the resulting overlap operator is found to be cheaper to construct and significantly better localized than the variety with the standard Wilson kernel.

mc/ms with Brillouin improved Wilson fermions

“…The selection of the specific subset of configurations was chosen such as to provide a wide enough window in the pion mass, the physical volume and the lattice spacing in order to allow for an extrapolation to the physical point. In the valence sector of our mixed action approach we use our recently developed Brillouin improved Wilson action [3]. As in our original publication of this fermion action, we perform a single step of APE-smearing on the gauge links to further improve gauge-noise and the approach to the continuum, as well as tree-level clover improvement (c SW = 1).…”

“…[3], to calculate m c /m s . Among a number of nice features, the Brillouin action has been shown to exhibit small cut-off effects even in the charm quark mass region when compared to regular clover-improved Wilson.…”

New fermion discretizations and their applications

“…2 we discuss generalization of Wilson fermions by using species-dependent mass terms, which we call "flavored-mass" [1,2,3]. In this study we will find new versions of Wilson, domain-wall and overlap fermions, some of which successfully have better dispersion relation and better eigenvalue spectrum [4]. In particular staggered-Wilson (overlap) fermions [1,5] have the possibility of reducing overlap computational costs [6,7] and reducing staggered taste breaking effectively [8,9].…”

“…In Sec. 4 we discuss another way of keeping chiral symmetry and reducing the number of flavors in the lattice fermion. "Minimal-doubling setup" reduces the species to two with keeping one exact chiral symmetry at the price of hypercubic symmetry [11,12,13].…”

Heavy Flavour Physics Review

“…[10]. Starting with the so-called Brillouin fermion action [11], a tree-level O(a 2 ) improved version of this action is introduced in Ref. [10] and tested numerically in quenched simulations for heavy quarks (am h 0.5).…”