Thu·Sep 20, 2007Thursday·September 20, 2007

1. 01*

   The spectrum of closed loops of fundamental flux in D=2+1 SU(N) gauge theories

   Andreas Athenodorou🇬🇧 · Barak Bringoltz🇺🇸 · Michael Teper🇬🇧

   We study the closed-string spectrum of SU(N) gauge theories in the fundamental representation in 2+1 dimensions. We calculate the energies of the lowest lying ~ 30 states using a large variety of operators characterised by the quantum numbers of parity and longitudinal momentum. We find that our results for the ground state are very well approximated by the Nambu-Goto (NG) predictions even for short strings. For the excited states, we observe significant deviations from the NG predictions only for very short strings and they decrease rapidly with increasing string length. Finally, we see that Nambu-Goto provides a much better description of our results than the effective string theoretical predictions. We discuss the continuum and large-N limits.

   hep-lathep-thPoS(2007)·3 citations
2. 02*

   Improved actions and lattice coarsening effects in MCRG studies in SU(2) LGT

   E.T. Tomboulis🇺🇸 · A. Velytsky🇺🇸

   We study decimation procedures and effective (improved) actions in the framework of Monte Carlo Renormalization Group (MCRG). Particular attention is paid to matching the form of the effective action to the decimation procedure parameters. Using the static quark-antiquark potential in SU(2) LGT we probe different distance scales and find that an effective action containing multiple group representations is capable of reproducing long distance physics well. In particular, appropriate matching results in the practical elimination of the coarsening/fining effect of the lattice spacing under decimation. The short distance regime of the effective theory is also studied. We next carry out studies of effective actions involving both multiple representations and loops beyond the single plaquette towards determining an improved action good over a wide length scale regime.

   hep-latPoS(2007)·3 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.