Dual quark condensate and dressed Polyakov loops

TL;DR

This paper introduces a new order parameter for finite temperature QCD based on the dual quark condensate, linking chiral symmetry and center symmetry through numerical lattice QCD analysis.

Contribution

It proposes the dual condensate as an order parameter, connecting the quark condensate with dressed Polyakov loops and demonstrating their duality numerically.

Findings

Dressed Polyakov loops are dominated by lowest Dirac modes.

The dual condensate responds differently to boundary conditions.

The dual condensate correlates with the Polyakov loop pattern.

Abstract

We construct a new order parameter for finite temperature QCD by considering the quark condensate for U(1)-valued temporal boundary conditions for the fermions. Fourier transformation with respect to the boundary condition defines the dual condensate. This quantity corresponds to an equivalence class of Polyakov loops, thereby being an order parameter for the center symmetry. We explore the duality relation between the quark condensate and these dressed Polyakov loops numerically, using quenched lattice QCD configurations below and above the QCD phase transition. It is demonstrated that the Dirac spectrum responds differently to changing the boundary condition, in a manner that reproduces the expected Polyakov loop pattern. We find the dressed Polyakov loops to be dominated by the lowest Dirac modes, in contrast to thin Polyakov loops investigated earlier.