Multigrid solvers for quantum dynamics - a first look

Scott MacLachlan

Delft Institute of Applied Mathematics
Delft University of Technology
Mekelweg 4, Room 07-270
2628 CD Delft
and
Centrum voor Wiskunde en Informatica, Amsterdam
The Netherlands



Abstract

The numerical study of lattice quantum chromodynamics (QCD) is an attempt to extract predictions about the world around us from the standard model of physics. Worldwide, there are several large collaborations on lattice QCD methods, with terascale computing power dedicated to these problems. Central to the computation in lattice QCD is the inversion of a series of fermion matrices, representing the interaction of quarks on a four-dimensional space-time lattice. In practical computation, this inversion may be approximated based on the solution of a set of linear systems. In this talk, I will present a basic description of the linear algebra problems in lattice QCD and why we believe that multigrid methods are well-suited to effectively solving them. While multigrid methods are known to be efficient solution techniques for many operators, those arising in lattice QCD offer new challenges, not easily handled by classical multigrid and algebraic multigrid approaches. The role of adaptive multigrid techniques in addressing the fermion matrices will be highlighted, along with preliminary results for several model problems.