QCD Anderson transition with overlap valence quarks on a twisted-mass sea -- an update

TL;DR

This study explores the localization of low-lying eigenmodes in QCD, examining their relation to chiral symmetry restoration and updating previous findings with improved analysis at various temperatures.

Contribution

It provides new estimates of the mobility edge in QCD using overlap valence quarks on twisted-mass sea configurations, challenging previous predictions about its behavior at the chiral transition.

Findings

The mobility edge does not vanish at the chiral transition temperature.

Localization of eigenmodes is closely related to chiral symmetry restoration.

Updated analysis includes lower temperatures and improved lattice spacing estimates.

Abstract

We investigate the QCD Anderson transition by studying the low-lying eigenmodes of the overlap operator in the background of gauge configurations with 2+1+1 quark flavors of twisted-mass Wilson fermions. The mobility edge, below which eigenmodes are localized, is estimated by the inflection point of the relative volume. The analysis of its temperature dependence suggests a close relation of localization to chiral symmetry restoration. We update our previous work [1] by including recent results on lower temperatures and switching to improved estimates of the lattice spacing and pseudocritical temperature respectively pion mass. Contrary to the previous prediction, our the mobility edge estimate does not vanish at the temperature of the chiral phase transition. We discuss a possible scenario, supported by literature, for why this could be the case. [1] R. Kehr, D. Smith and L. von Smekal, QCD Anderson transition with overlap valence quarks on a twisted-mass sea, Phys. Rev. D 109 (2024) 074512 [2304.13617].