Correlations of topological objects and quarks in hadrons

Abstract

We study topological properties of the QCD vacuum on an 8 3 ϫ4 lattice at finite temperature in both phases of QCD. We analyze the distributions of instanton and monopole densities around static color sources and find a suppression of the densities close to external sources. In the confinement phase the suppression occurs in the whole flux tube between a static quark-antiquark pair. We investigate the relation between instantons and Abelian projected monopoles by calculating local correlation functions between topological charge densities and monopole densities. It turns out that topological quantities are correlated over approximately two lattice spacings. The monopole-instanton correlations are rather insensitive under cooling of gauge fields.

Confining string and its widening inHP1embedding approach

“…Although it had been known for some time [13,14] that confining string suppresses the topological fluctuations, we were able to investigate the problem in details and to show, in particular, that the confining flux tube in terms of the topological density corresponds likely to the fluctuating string. Moreover, we confirmed the generically expected logarithmic string widening and we attempted also to estimate the characteristic string scales.…”

“…First, we refrain from using the cooling approach because it certainly wipes out local topology of the real (uncooled) vacuum. Indeed, the fluctuations of the topological charge inside the chromoelectric string were found to depend crucially upon the cooling parameters [13,14] and therefore are affected by uncontrollable systematic errors. Other essential simplifications used in this paper are as follows:…”

“…The investigation was developed further in Ref. [14] with the help of the same cooling method which is a gradual transformation of the quantum ("hot") fields towards the classical ("cold") vacuum. The cooling is aimed to reduce the topologically trivial effects of divergent zero-point fluctuations.…”

Magnetic monopoles, center vortices and topology of gauge fields

“…However, in the maximum Abelian gauge correlations between instantons and monopoles has been found, in both analytical and lattice studies [3].…”

Visualization of topological objects in QCD

“…Instantons are supposed to cause confinement in QCD if they form a so-called instanton liquid. In a series of papers we have presented evidence that there exist local correlations between these topological objects on the basis of gauge field averages [1]. In this contribution we present a graphical approach to this subject by visualization of specific SU (2) gluon configurations.…”