Towards finite density QCD with Taylor expansions

TL;DR

This paper investigates the convergence of Taylor expansions in lattice QCD at finite density using an effective Polyakov-quark-meson model, introducing a new computational technique to improve the analysis of the QCD phase diagram.

Contribution

It applies a novel algorithmic method to calculate higher-order Taylor coefficients in an effective QCD model, aiding the study of phase boundaries and critical points.

Findings

Higher-order Taylor coefficients can be accurately computed with the new technique.

The results provide insights into the location of the QCD critical endpoint.

Comparison with full model solutions validates the effectiveness of the approach.

Abstract

Convergence properties of Taylor expansions of observables, which are also used in lattice QCD calculations at non-zero chemical potential, are analyzed in an effective N_f = 2+1 flavor Polyakov-quark-meson model. A recently developed algorithmic technique allows the calculation of higher-order Taylor expansion coefficients in functional approaches. This novel technique is for the first time applied to an effective N_f = 2+1 flavor Polyakov-quark-meson model and the findings are compared with the full model solution at finite densities. The results are used to discuss prospects for locating the QCD phase boundary and a possible critical endpoint in the phase diagram.