Topological Susceptibility in Two Flavors Lattice QCD with the Optimal Domain-Wall Fermion

Abstract

We determine the topological susceptibility of the gauge configurations generated by lattice simulations using two flavors of optimal domain-wall fermion on the $16^3\times 32$ lattice with length 16 in the fifth dimension, at the lattice spacing $a\simeq 0.1$ fm. Using the adaptive thick-restart Lanczos algorithm, we project the low-lying eigenmodes of the overlap Dirac operator, and obtain the topological charge of each configuration, for eight ensembles with pion masses in the range $220-550$ MeV. From the topological charge, we compute the topological susceptibility and the second normalized cumulant. Our result of the topological susceptibility agrees with the sea-quark mass dependence predicted by the chiral perturbation theory and provides a determination of the chiral condensate, ${\Sigma }^{\overline{MS}}(2GeV)=[259(6)(7)MeV{]}^3$, and the pion decay constant $F_{\pi }=92(12)(2)$ MeV.

Comments: 10 pages, 3 EPS figures, v2: typos corrected, to appear in Phys. Lett. B