Multi-boson block factorization of fermions

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

^* Speaker, e-mail: Leonardo.Giusti@cern.ch.

Published online: 26 March 2018

Abstract

The numerical computations of many quantities of theoretical and phenomenological interest are plagued by statistical errors which increase exponentially with the distance of the sources in the relevant correlators. Notable examples are baryon masses and matrix elements, the hadronic vacuum polarization and the light-by-light scattering contributions to the muon g – 2, and the form factors of semileptonic B decays. Reliable and precise determinations of these quantities are very difficult if not impractical with state-of-the-art standard Monte Carlo integration schemes. I will review a recent proposal for factorizing the fermion determinant in lattice QCD that leads to a local action in the gauge field and in the auxiliary boson fields. Once combined with the corresponding factorization of the quark propagator, it paves the way for multi-level Monte Carlo integration in the presence of fermions opening new perspectives in lattice QCD. Exploratory results on the impact on the above mentioned observables will be presented.