Improving the Quark Number Susceptibilities for Staggered Fermions

TL;DR

This paper develops an improved method for calculating quark number susceptibilities with staggered fermions, achieving closer approximation to the continuum ideal gas limit on small lattice sizes, thus aiding lattice QCD studies at high temperatures.

Contribution

The authors introduce an improved number density and susceptibility formulation for staggered fermions that better approximates the continuum limit on small lattices.

Findings

Improved susceptibilities approach the ideal gas limit more accurately.

Constructed susceptibilities are consistent with current conservation.

Method reduces lattice artifacts at small N_t.

Abstract

Quark number susceptibilities approach their ideal gas limit at sufficiently high temperatures. As in the case of other thermodynamic quantities, this limit itself is altered substantially on lattices with small temporal extent, N_t = 4-8, making it thus difficult to check the validity of perturbation theory. Unlike other observables, improving susceptibilities or number densities is subject to constraints of current conservation and absence of chemical potential dependent divergences. We construct such an improved number density and susceptibility for staggered fermions and show that they approximate the continuum ideal gas limit better on small temporal lattices.