A faster method of computation of lattice quark number susceptibilities

TL;DR

This paper introduces a faster computational method for quark number susceptibilities in lattice QCD by reducing the number of required propagators, enabling more efficient higher-order susceptibility calculations relevant for locating the QCD critical point.

Contribution

A novel, more efficient method for computing quark number susceptibilities in lattice QCD that simplifies calculations and improves the accuracy of higher-order susceptibility ratios.

Findings

The new method reduces computational effort for susceptibility calculations.

The subtraction procedure effectively removes lattice artifacts.

Ratios of susceptibilities are stable and useful for critical point estimates.

Abstract

We compute the quark number susceptibilities in two flavor QCD for staggered fermions by adding the chemical potential as a Lagrange multiplier for the point-split number density term. Since lesser number of quark propagators are required at any order, this method leads to faster computations. We propose a subtraction procedure to remove the inherent undesired lattice terms and check that it works well by comparing our results with the existing ones where the elimination of these terms is analytically guaranteed. We also show that the ratios of susceptibilities are robust, opening a door for better estimates of location of the QCD critical point through the computation of the tenth and twelfth order baryon number susceptibilities without significant additional computational overload.