The curvature of the chiral pseudocritical line from LQCD: analytic continuation and Taylor expansion compared

TL;DR

This paper compares two methods, Taylor expansion and analytic continuation, for determining the curvature of the chiral pseudocritical line in lattice QCD, finding consistent results that validate both approaches.

Contribution

It provides a direct comparison of Taylor expansion and analytic continuation methods for calculating the curvature in lattice QCD, confirming their consistency at the physical point.

Findings

Continuum extrapolated curvature $ppa = 0.0145(25)$ from Taylor expansion.

Analytic continuation estimate of $ppa = 0.0135(20)$ in the same scheme.

Excellent agreement between the two methods confirms their reliability.

Abstract

We present a determination of the curvature $\kappa$ of the chiral pseudocritical line from $N_f=2+1$ lattice QCD at the physical point obtained by adopting the Taylor expansion approach. Numerical simulations performed at three lattice spacings lead to a continuum extrapolated curvature $\kappa = 0.0145(25)$, a value that is in excellent agreement with continuum limit estimates obtained via analytic continuation within the same discretization scheme, $\kappa = 0.0135(20)$. The agreement between the two calculations is a solid consistency check for both methods.