HEP Lattice·hep-lat
6 papers—6 primary·0 cross-listed·reconstructed*
I summarize recent developments in spectrum calculations using Kogut-Susskind quarks. Theoretical developments include one-loop computations with improved actions. I present some recent simulation results, mostly from a MILC collaboration project using three flavors. Effects of dynamical quarks are clearly seen in the isovector 0++ meson propagator and in the mass ratio ``J''.
V.A. Belavin🇷🇺 · M.I. Polikarpov🇷🇺 · A.I. Veselov🇷🇺
We study the structure of the isolated static monopoles in the maximal Abelian projection of SU(2) lattice gluodynamics. Our estimation of the monopole radius is .
M. Engelhardt🇩🇪 · M. Faber🇦🇹 · H. Reinhardt🇩🇪
A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic vortices represented by (closed) random surfaces, is presented. The model quantitatively describes both confinement (including the finite-temperature transition to a deconfined phase) and the topological susceptibility of the Yang-Mills ensemble. A first (quenched) study of the spectrum of the Dirac operator furthermore yields a behavior for the chiral condensate which is compatible with results obtained in lattice gauge theory.
H. Satz🇩🇪
Continuous phase transitions in spin systems can be formulated as percolation of suitably defined clusters. We review this equivalence and then discuss how in a similar way, the color deconfinement transition in SU(2) gauge theory can be treated as a percolation phenomenon. In the presence of an external field, spin systems cease to show thermal critical behavior, but the geometric percolation transition persists (Kertész line). For , we study the relation between percolation and pseudocritical behavior, both for continuous and first order transitions, and show that it leads to the necessity of an -dependent cluster definition. A viable formulation of this kind could serve as definition of deconfinement in QCD with dynamical quarks.
T. Schulze🇩🇪 · J. Engels🇩🇪 · S. Holtmann🇩🇪 · T. Mendes (University Bielefeld, Germany)🇧🇷
We calculate numerically universal finite-size-scaling functions of the magnetization for the three-dimensional O(4) and O(2) spin models. The approach of these functions to the infinite-volume scaling functions is studied in detail on the critical and pseudocritical lines. For this purpose we determine the pseudocritical line in two different ways. We find that the asymptotic form of the finite-size-scaling functions is already reached at small values of the scaling variable. A comparison with QCD lattice data for two flavours of staggered fermions shows a similar finite-size behaviour which is compatible with that of the spin models.
Christof Gattringer🇩🇪 · Meinulf Göckeler🇩🇪 · C.B. Lang🇦🇹 · P.E.L. Rakow🇩🇪 · Stefan Schaefer🇩🇪 · Andreas Schäfer🇩🇪
We discuss the construction and properties of an approximate solution of the Ginsparg-Wilson equation, the so-called chirally improved lattice Dirac operator. In particular we study the behavior of its eigenmodes in smooth instanton backgrounds as well as for thermalized gauge configurations on both sides of the QCD phase transition. We compare with results from other Dirac operators including the overlap operator. The results support the picture of chiral symmetry breaking being closely related to instantons.
* 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.