The Static Quark-Antiquark Potential: A ``Classical'' Experiment On The Connection Machine CM-2

We describe the Wuppertal university pilot project in applied parallel computing. We report on a comprehensive high statistics determination of the static quark-antiquark potential and related quantities from quenched quantum chromodynamics. New data for the string tension and the plaquette action for the region 5.5 < beta < 6.8 is presented.Comment: (Talk K. Schilling), 11 pages, postscript (\approx 250K

Quark-Antiquark Forces From SU(2) and SU(3) Gauge Theories on Large Lattices

We present results on the spin-independent quark-antiquark potential in SU(3) gauge theory from a simulation on a 48^3*64 lattice at Beta = 6.8, corresponding to a volume of (1.7 fm)^3. Moreover, a comprehensive analysis of spin- and velocity-dependent potentials is carried out for SU(2) gauge theory, with emphasis on the short range structure, on lattices with resolutions ranging from .02 fm to .04 fm.Comment: 10 pages, uucompressed latex with 5 ps figures, epsf style require

Glueball and gluelump spectrum in abelian projected QCD

We study glueball and gluelump spectra calculated after abelian projection in both quenched and $N_f=2$ full QCD. The abelian projection is made after MA gauge fixing. We demonstrate that both spectra can be recovered despite the problem with positivity. We suggest the interpretation of some of the gluelump states in the language of the abelian projected theory.Comment: Lattice 2001(confinement), 3 page

Disturbing Extremal Behavior of Spot Rate Dynamics

This paper presents a study of extreme interest rate movements in the U.S. Federal Funds market over almost a half century of daily observations from the mid 1950s through the end of 2000. We analyze the fluctuations of the maximal and minimal changes in short term interest rates and test the significance of time-varying paths followed by the mean and volatility of extremes. We formally determine the relevance of introducing trend and serial correlation in the mean, and of incorporating the level and GARCH effects in the volatility of extreme changes in the federal funds rate. The empirical findings indicate the existence of volatility clustering in the standard deviation of extremes, and a significantly positive relationship between the level and the volatility of extremes. The results point to the presence of an autoregressive process in the means of both local maxima and local minima values. The paper proposes a conditional extreme value approach to calculating value at risk by specifying the location and scale parameters of the generalized Pareto distribution as a function of past information. Based on the estimated VaR thresholds, the statistical theory of extremes is found to provide more accurate estimates of the rate of occurrence and the size of extreme observations.extreme value theory, volatility, interest rates, value at risk

Chromofields of Strings and Baryons

We calculate color electric fields of quark/antiquark ($\bar{q}q$) and 3 quark ($qqq$) systems within the chromodielectric model (CDM). We explicitly evaluate the string tension of flux tubes in the $\bar{q}q$--system and analyze their profile. To reproduce results of lattice calculations we use a bag pressure $B = (320 MeV)^4$ from which an effective strong coupling constant $\alpha_s \approx 0.3$ follows. With these parameters we get a $Y$ shaped configuration for large $qqq$--systems.Comment: Contributions to QNP 2002, Quarks and Nuclear Physics, Juelich, Germany 3 pages, 10 eps figure

First Evidence of NfN_f-Dependence in the QCD Interquark Potential

We present a lattice calculation of the interquark potential between static quarks in a ``full'' QCD simulation with 2 flavours of dynamical Wilson-quarks at three intermediate sea-quark masses. We work at $\beta = 5.6$ on lattice size of $16^3 \times 32$ with 100 configurations per sea-quark mass. We compare the full QCD potential with its quenched counterpart at equal lattice spacing, $a^{-1} \simeq 2.0$ GeV, which is at the onset of the quenched scaling regime. We find that the full QCD potential lies consistently below that of quenched QCD. We see no evidence for string-breaking effects on these lattice volumes, $V \simeq (1.5\,\,{\rm fm})^3$.Comment: 9 pages (1 tex file epsf-style + 6 ps-figures