Local multiboson factorization of the quark determinant

¹ Helmholtz-Institut Mainz, Johannes Gutenberg-Universität, Staudingerweg 18, 55128 Mainz, Germany
² Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
³ INFN, sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
⁴ Theoretical Physics Department, CERN, Geneva, Switzerland
⁵ Dipartimento di Fisica, Università di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁶ INFN, sezione di Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁷ John von Neumann Institute for Computing (NIC), DESY, Platanenallee 6, 15738 Zeuthen, Germany

^* Speaker, e-mail: marco.ce@uni-mainz.de, HIM-2017-06, CERN-TH-2017-221, DESY-17-167

Published online: 26 March 2018

Abstract

We discuss the recently proposed multiboson domain-decomposed factorization of the gauge-field dependence of the fermion determinant in lattice QCD. In particular, we focus on the case of a lattice divided in an arbitrary number of thick time slices. As a consequence, multiple space-time regions can be updated independently. This allows to address the exponential degradation of the signal-to-noise ration of correlation functions with multilevel Monte Carlo sampling. We show numerical evidence of the effectiveness of a two-level integration for pseudoscalar propagators with momentum and for vector propagators, in a two active regions setup. These results are relevant to lattice computation of the hadronic contributions to the anomalous magnetic moment of the muon and to heavy meson decay form factors.