Dirac mode localization in QCD near the crossover temperature

Abstract

We study the localization properties of the low-lying Dirac eigenmodes in QCD near the crossover temperature, using stout-smeared staggered fermions and Symanzik-improved gauge action on the lattice. On $N_{\mathrm{t}}=8$ lattices we find that localized low modes, absent at low temperature, appear at a temperature $T_{\mathrm{loc}}$ in the range $150\mathrm{MeV}\le T_{\mathrm{loc}}\le 160\mathrm{MeV}$, well within the chiral crossover range as determined from the chiral condensate and from the light-quark susceptibility. Since with our choice of lattice action neither the chiral transition region nor the renormalized mobility edges change significantly above $N_{\mathrm{t}}=8$, our conclusion that $T_{\mathrm{loc}}$ is in the chiral crossover region is expected to remain valid in the continuum limit.

Revised version, to appear in PRD; 12 pages, 6 figures