2007/05/31 by JLQCD, Hidenori Fukaya, TWQCD collaboration +14 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-lat
paper · pdf · doi:10.1103/physrevd.76.054503
published as Phys.Rev.D76:054503,2007 · 28pages, 12figures, accepted version
openalex publication_date 2007/09/13 · arxiv created 2007/10/28 · arxiv updated 2012/08/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The low-lying eigenvalue spectrum of the QCD Dirac operator in the ϵ regime is expected to match with that of chiral random matrix theory (ChRMT). We study this correspondence for the case including sea quarks by performing two-flavor QCD simulations on the lattice. Using the overlap fermion formulation, which preserves exact chiral symmetry at finite lattice spacings, we push the sea quark mass down to \ensuremath∼3 MeV on a 163\ifmmode×\else\texttimes\fi32 lattice at a lattice spacing a\ensuremath≃0.11 fm. We compare the low-lying eigenvalue distributions and find a good agreement with the analytical predictions of ChRMT. By matching the lowest-lying eigenvalue we extract the chiral condensate, \ensuremathΣ^MS(2 GeV)=(251\ifmmode±\else\textpm\fi7\ifmmode±\else\textpm\fi11 MeV)3, where errors represent statistical and higher order effects in the ϵ expansion. We also calculate the eigenvalue distributions on the lattices with heavier sea quarks at two lattice spacings. Although the ϵ expansion is not applied for those sea quarks, we find a reasonable agreement of the Dirac operator spectrum with ChRMT. The value of \ensuremathΣ, after extrapolating to the chiral limit, is consistent with the estimate in the ϵ regime.