Universal and non-universal finite-volume effects in the vicinity of chiral phase transition in (2+1)-flavor QCD

TL;DR

This study analyzes finite-volume effects on the chiral phase transition in (2+1)-flavor QCD using lattice simulations, highlighting how finite-size scaling impacts the extrapolation to infinite volume and the determination of transition temperature.

Contribution

It provides a detailed finite-size scaling analysis of the chiral order parameter in lattice QCD with improved staggered quarks, including deviations from expected scaling behavior.

Findings

Infinite volume extrapolated data agree with $O(2)$ scaling behavior.

Finite-size effects significantly influence the estimation of the chiral transition temperature.

Quantified deviations from asymptotic scaling for various quark masses and volumes.

Abstract

In this proceeding, we discuss the finite-size scaling analysis of the order parameter related to the chiral phase transition in QCD with two massless quarks. We use data obtained in lattice QCD calculations performed with highly improved staggered quarks (HISQ) for a range of light quark masses, $1/240 \leq m_\ell/m_s \leq 1/27$ for different spatial volumes ($N_\sigma$) on Euclidean lattices with temporal extent $N_\tau=8$, satisfying $3\,N_\tau \leq N_\sigma \leq 10\,N_\tau$. We observe that infinite volume extrapolated data for the order parameter agree reasonably well with the expected $O(2)$ scaling behavior even for physical ratios of the light-to-strange quark mass ratio. We quantify deviations from asymptotic scaling and perform a detailed analysis of the influence of finite-size effects in terms of temperature and quark masses at a fixed lattice cutoff. This is crucial for improving the reliability of the infinite-volume extrapolated estimate of the chiral order parameter and for a more precise determination of chiral phase transition temperature from direct Lattice QCD simulations.