Wed·Aug 21, 2002Wednesday·August 21, 2002

1. 01*

   Non-compact QED_3 with N_f >=2

   S.J. Hands🇬🇧 · J.B. Kogut🇺🇸 · C.G. Strouthos🇬🇧

   Non-compact three-dimensional QED is studied by computer simulations to understand its chiral symmetry breaking features for N_f>=2, on lattice volumes up to 50^3 and bare masses as low as ma=0.0000625. We compute the chiral condensate, scalar and pseudoscalar susceptibilities, and the masses of scalar and pseudoscalar mesons. Finite volume effects and discretisation artifacts are carefully monitored. Our results reveal no decisive signal for chiral symmetry breaking for any N_f>=2. For N_f=2 the dimensionless condensate can be bounded by beta^2<psibarpsi> <= 5x10^-5. We also present an exploratory study of the fractionally-charged Polyakov line.

   hep-latcond-mat.supr-conhep-thNPB(2002)·110 citations
2. 02*

   The local structure of topological charge fluctuations in QCD

   I. Horvath🇺🇸 · S.J. Dong🇺🇸 · T. Draper🇺🇸 · F.X. Lee🇺🇸 · K.F. Liu🇺🇸 · J.B. Zhang🇦🇺 · H.B. Thacker🇺🇸

   We introduce the Dirac eigenmode filtering of topological charge density associated with Ginsparg-Wilson fermions as a tool to investigate the local structure of topological charge fluctuations in QCD. The resulting framework is used to demonstrate that the bulk of topological charge in QCD does not appear in the form of unit quantized lumps. This means that the mixing of "would-be" zeromodes associated with such lumps is probably not the prevalent microscopic mechanism for spontaneous chiral symmetry breaking in QCD. To characterize the coherent local behavior in topological charge density at low energy, we compute the charges contained in maximal coherent spheres enclosing non-overlapping peaks. We find a continuous distribution essentially ending at ~0.5. Finally, we study, for the first time, the overlap-operator topological-charge-density correlators and find consistency with non-positivity at nonzero physical distance. This represents a non-trivial check on the locality (in gauge paths) of the overlap Dirac operator for realistic gauge backgrounds.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·8 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.