Correlations and the Dirac Structure of the Nucleon Self-Energy

The Dirac structure of the nucleon self-energy in symmetric nuclear matter as well as neutron matter is derived from a realistic meson exchange model for the nucleon-nucleon (NN) interaction. It is demonstrated that the effects of correlations on the effective NN interaction in the nuclear medium can be parameterized by means of an effective meson exchange. This analysis leads to a very intuitive interpretation of correlation effects and also provides an efficient parametrization of an effective interaction to be used in relativistic structure calculations for finite nuclei.Comment: 16 pages, 11 Figures include

Matter near to the Endpoint of the Electroweak Phase Transition

Wave functions and the screening mass spectrum in the 3D SU(2)-Higgs model near to the phase transition line below the endpoint and in the crossover region are calculated. In the crossover region the changing spectrum versus temperature is examined showing the aftermath of the phase transition at lower Higgs mass. Large sets of operators with various extensions are used allowing to identify wave functions in position space.Comment: 3 pages, 8 figures, LaTex+espcrc2.sty; LATTICE98(electroweak

Reply to ``Comment on `Test of constancy of speed of light with rotating cryogenic optical resonators' ''

An improved analysis of the Michelson-Morley-type experiment by P. Antonini et al. (Phys. Rev. A. 71, 050101 (2005)) yields the Robertson-Mansouri-Sexl theory parameter combination $\beta-\delta-1/2=(-0.6\pm 2.1\pm 1.2)\cdot10^{-10}$ and the Standard Model Extension theory parameter $(\tilde{\kappa}_{e-})^{ZZ} = (-2.9\pm 2.2)\cdot 10^{-14}$.Comment: 2 page

Confinement, deconfinement and the photon propagator in 3D cQED on the lattice

We report on a lattice study of the gauge boson propagator of 3D compact QED in Landau gauge at zero and finite temperature. Non-perturbative effects are reflected by the generation of a mass m and by an anomalous dimension alpha. These effects can be attributed to monopoles and are absent in the propagator of the regular part of the gauge field.Comment: 3 pages, 4 figures, talk presented by A.S. at 5th International Conference on Quark Confinement and the Hadron Spectrum, Gargnano, Italy, 10-14 Sep 200

Studying the infrared region in Landau gauge QCD

We report on the progress we made in studying the infrared behavior of the ghost and gluon dressing functions in Landau gauge. Related to this we also investigate a running coupling given in terms of those functions and compare our results to those coming from the Dyson-Schwinger approach. We present first numerical results for the SU(3) ghost-ghost-gluon vertex renormalization constant. In addition the spectrum of low-lying eigenvalues and eigenfunctions of the Faddeev-Popov operator is determined. The saturation of the ghost propagator in terms of those eigenvalues and eigenmodes is discussed at lower momenta.Comment: 6 pages, 4 figures, talk presented at Lattice 2005 (Topology and Confinement

The influence of Gribov copies on the gluon and ghost propagator

The dependence of the gluon and ghost propagator in pure SU(3) gauge theory on the choice of Gribov copies in Landau gauge is studied. Simulations were performed on several lattice sizes at $\beta$=5.8, 6.0 and 6.2. In the infrared region the ghost propagator turns out to depend on the choice, while the impact on the gluon propagator is not resolvable. Also the eigenvalue distribution of the Faddeev-Popov operator is sensitive to Gribov copies.Comment: Talk presented at Quark Confinement and the Hadron Spectrum VI, Villasimius, Sardinia, Italy, September 21-25, 2004, 3 pages, 2 figure