Investigating efficient methods for computing four-quark correlation functions

We discuss and compare the efficiency of various methods, combinations of point-to-all propagators, stochastic timeslice-to-all propagators, the one-end trick and sequential propagators, to compute two-point correlation functions of two-quark and four-quark interpolating operators of different structure including quark–antiquark type, mesonic molecule type, diquark–antidiquark type and two-meson type. Although we illustrate our methods in the context of the a0(980), they can be applied for other multi-quark systems, where similar diagrams appear. Thus our results could provide helpful guidelines on the choice of methods for correlation function computation for future lattice QCD studies of meson–meson scattering and possibly existing tetraquark states.