Lattice QCD and Particle Physics
Contribution from the USQCD Collaboration to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021).
arXiv subjects
Publications and source records attributed to Paul Mackenzie.
Contribution from the USQCD Collaboration to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021).
In October, 2016, the US Department of Energy launched the Exascale Computing Project, which aims to deploy exascale computing resources for science and engineering in the early 2020's. The project brings together application teams, software developers, and hardware vendors in order to realize this goal. Lattice QCD is one of the applications. Members of the US lattice gauge theory community with significant collaborators abroad are developing algorithms and software for exascale lattice QCD calculations. We give a short description of the project, our activities, and our plans.
A quick review of the features of FermiQCD, a C++ library for fast development of parallel Lattice QCD applications. FermiQCD is fully Object Oriented and is based on MPI but, it required no previsius knowledge of parallel programming. It includes parallel algorithms for Wilson, Clover, Staggered, Asqtad and Domain Wall fermions. Optimizations are based on M. Luescher's SSE2 macros.
We present results from a systematic perturbative investigation of taste-changing in improved staggered quarks. We show one-loop taste-changing interactions can be removed perturbatively by an effective four-quark term and calculate the necessary coefficients.
We perform a nonperturbative tuning of the coefficients in the $O(a^2)$ improved action for staggered fermions. The mass splitting for the pions of different doubler flavor is used as a measure of the symmetry breaking effects introduced by $O(a^2)$ discretization errors. We find that the flavor nondegeneracy can be somewhat reduced but not eliminated by such a tuning, indicating the need for new terms in the action to reduce the nondegeneracy.