Center clusters in full QCD at finite temperature and background magnetic field

TL;DR

This study investigates the structure of center clusters in full QCD at finite temperature and magnetic field, revealing fractal properties and percolation behavior that inform the QCD phase diagram and potential models of heavy-ion collisions.

Contribution

It provides the first continuum-extrapolated lattice analysis of center cluster fractality and percolation in full QCD under magnetic fields, connecting these properties to phase transition characteristics.

Findings

Fractal dimension of clusters is less than three near the transition.

Vanishing mean free path inside clusters suggests a unique medium structure.

Percolation probability helps define the transition temperature.

Abstract

We study the center structure of full dynamical QCD at finite temperatures and nonzero values of the background magnetic field using continuum extrapolated lattice data. We concentrate on two particular observables characterizing center clusters: their fractality and the probability for percolation. For temperatures below and around the transition region, the fractal dimension is found to be significantly smaller than three, leading to a vanishing mean free path inside the cluster structure. This finding might be relevant for center symmetry-based models of heavy-ion collisions. In addition, the percolation probability is employed to define the transition temperature and to map out the QCD phase diagram in the magnetic field-temperature plane.