Improved Pseudofermion Approach for All-Point Propagators

TL;DR

This paper introduces an improved pseudofermion method with mode-shifting to efficiently compute all-point quark propagators, reducing critical slowing down and applicable to various quark actions, enhancing unquenched QCD calculations.

Contribution

The paper presents a novel pseudofermion approach with mode-shifting that addresses critical slowing down and is compatible with multiple quark actions, improving computational efficiency.

Findings

Reduces critical slowing down for light quarks

Applicable to multiple quark actions including Wilson and overlap

Enables extraction of full physical content from gauge configurations

Abstract

Quark propagators with arbitrary sources and sinks can be obtained more efficiently using a pseudofermion method with a mode-shifted action. Mode-shifting solves the problem of critical slowing down (for light quarks) induced by low eigenmodes of the Dirac operator. The method allows the full physical content of every gauge configuration to be extracted, and should be especially helpful for unquenched QCD calculations. The method can be applied for all the conventional quark actions: Wilson, Sheikoleslami-Wohlert, Kogut-Susskind, as well as Ginsparg-Wilson compliant overlap actions. The statistical properties of the method are examined and examples of physical processes under study are presented.