Fri·Aug 3, 2007Friday·August 3, 2007

1. 01*

   Restless pions: orbifold boundary conditions and noise suppression in lattice QCD

   Paulo F. Bedaque🇺🇸 · Andre Walker-Loud🇺🇸

   The study of one or more baryons in lattice QCD is severely hindered by the exponential decay in time of the signal-to-noise ratio. The rate at which the signal-to-noise decreases is a function of the the pion mass. More precisely, it depends on the minimum allowed pion energy in the box, which, for periodic boundary conditions, is equal to its mass. We propose a set of boundary conditions, given by a "parity orbifold'' construction, which eliminates the zero momentum pion modes, raising the minimum pion energy without altering the QCD ground state, and thereby improving the signal-to-noise ratio of (multi)-baryon correlation functions at long Euclidean times. We discuss variations of these "restless pions" boundary conditions and focus on their impact on the study of nuclear forces.

   hep-lathep-phhep-thnucl-thPLB(2008)·11 citations
2. 02*

   Spectral properties of quarks above T_c in quenched lattice QCD

   Frithjof Karsch🇺🇸 · Masakiyo Kitazawa🇯🇵

   We analyze the quark spectral function above the critical temperature for deconfinement in quenched lattice QCD using clover improved Wilson fermions in Landau gauge. We show that the temporal quark correlator is well reproduced by a two-pole approximation for the spectral function and analyze the bare quark mass dependence of both poles as well as their residues. In the chiral limit we find that the quark spectral function has two collective modes which correspond to the normal and plasmino excitations. At large values of the bare quark mass the spectral function is dominated by a single pole.

   hep-lathep-phPLB(2007)·36 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.