Polynomial Filtered HMC: An Algorithm for lattice QCD with dynamical quarks

Abstract

Polynomial approximations to the inverse of the fermion matrix are u sed to filter the dynamics of the upper energy scales in HMC simulations. The use of a multiple time-scale integration sc heme allows the filtered pseudofermions to be evolved using a coarse step size. We introduce a novel generalisatio n of the nested leapfrog which allows for far greater flexibility in the choice of time scales. We observe a reduction in the com putational expense of the molecular dynamics integration of between 3–5 which improves as the quark mass decre ases.