Topological susceptibility from the overlap

Luigi Del Debbio, Claudio Pica

Research output: Contribution to journalArticlepeer-review

Abstract

The chiral symmetry at finite lattice spacing of Ginsparg-Wilson fermionic actions constrains the renormalization of the lattice operators; in particular, the topological susceptibility does not require any renormalization, when using a fermionic estimator to define the topological charge. Therefore, the overlap formalism appears as an appealing candidate to study the continuum limit of the topological susceptibility while keeping the systematic errors under theoretical control. We present results for the SU(3) pure gauge theory using the index of the overlap Dirac operator to study the topology of the gauge configurations. The topological charge is obtained from the zero modes of the overlap and using a new algorithm for the spectral flow analysis. A detailed comparison with cooling techniques is presented. Particular care is taken in assessing the systematic errors. Relatively high statistics (500 to 1000 independent configurations) yield an extrapolated continuum limit with errors that are comparable with other methods. Our current value from the overlap is $\chi^{1/4} = 188 \pm 12 \pm 5 \MeV$.
Original languageEnglish
Number of pages16
JournalJournal of High Energy Physics
Volume2004
Issue number02
DOIs
Publication statusPublished - 22 Sep 2003

Keywords

  • hep-lat
  • Nonperturbative Effects
  • Lattice Gauge Field Theories
  • Lattice QCD

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