1) Solid evidence exists that dual superconductivity 1,2,3 is the mechanism of colour confinement. 2) The Witten-Veneziano 6,7 formula for the mass of the η is definitely correct. This statement has been made possible by the construction of an improved (almost perfect) operator for the topological charge density. By use of the same technical improvement a detailed study of the topological susce...

We consider a recent proposal by Horváth et al. to address the question whether topological charge fluctuations in QCD are instanton dominated via the response of fermions using lattice fermions with exact chiral symmetry, the overlap fermions. Considering several volumes and lattice spacings we find strong evidence for chirality of a finite density of low-lying eigenvectors of the overlap-Dira...

The topological charge is constructed for SU(3) center vortex world-surfaces composed of elementary squares on a hypercubic lattice. In distinction to the SU(2) case investigated previously, it is necessary to devise a proper treatment of the color structure at vortex branchings, which arise in the SU(3) case, but not for SU(2). The construction is used to evaluate the topological susceptibilit...

Correlations of the topological charge Q, the electric current J and the magnetic current J in SU(2) lattice gauge theory in the Maximal Abelian projection are investigated. It occurs that the correlator ≪ QJJ ≫ is nonzero for a wide range of values of the bare charge. It is shown that: (i) the abelian monopoles in the Maximal Abelian projection are dyons which carry fluctuating electric charge...

Andreas Schäfer Universität Regensburg, Institut für Physik, 93040 Regensburg, Germany E-mail: [email protected] We systematically compare three filtering methods used to extract topological excitations from lattice gauge configurations, namely smearing, Laplace filtering and the filtered fermionic topological charge (with chirally improved fermions). Each of these techn...

Recent progress in understanding the emergence of confinement and other nonperturbative effects in the strong interaction vacuum is reviewed. Special emphasis is placed on the role of different types of collective infrared gluonic degrees of freedom in this respect. After a survey of complementary approaches, models of the QCD vacuum based on center vortices, Abelian magnetic monopoles and topo...

We present a study of the imaging of the interference of spatial-helical modes of single photons. This work includes a mathematical treatment that accounts for the direction of propagation and spatial mode degrees of freedom in the situation where light travels through an interferometer that prepares the light in distinct spatial modes and makes them interfere. We present results of the interfe...

The Leutwyler-Smilga prediction regarding the (ir)relevance of the global topological charge for QCD in a finite box is subject to a test. To this end the lattice version of a suitably chosen analogue (massive 2-flavour Schwinger model) is analyzed in the small (V Σm≪ 1), intermediate (V Σm ≃ 1) and large (V Σm≫ 1) Leutwyler-Smilga regimes. The predictions for the small and large regimes are co...

Topological charge distributions of SU(3) gauge theory at finite temperature are calculated on the lattice with high statistics in a manner of free from the uncertainty of β-function. Clear temperature dependence of the topological charge distribution is obtained. Combining the present result with the recent study about the relation between the masses of η meson system and the gauge field topol...

We study quenched and dynamical pion correlators in the two-flavour Schwinger model (2D QED) both within topological charge sectors and averaged. The results show that a clean-cut definition of a pion mass is no longer possible if tunneling between sectors does not occur.