In this thesis algorithmic improvements and variants for two-flavor lattice QCD simulations with dynamical fermions are studied using the O(a) improved Dirac-Wilson operator in the Schrödinger functional setup and employing a hybrid Monte Carlo-type (HMC) update. Both, the Hermitian and the Non-Hermitian operator are considered. For the Hermitian Dirac-Wilson operator we investigate the advanta...

The improvement of the lattice QCD action has become recently a main focus of research in lattice field theory. Improved actions for lattice QCD are designed to remove lattice-spacing artifacts in numerical estimates of physical observables. This allows to conduct the numerical calculations on much coarser and smaller lattices and thereby to substantially reduce the simulation costs. In this co...

Knowledge discovery in databases, commonly referred to as data mining, has attracted enormous research efforts from different domains such as databases, statistics, artificial intelligence, data visualization, and so forth in the past decade. Most of the research work in data mining such as clustering, association rules mining, and classification focus on discovering large patterns from databas...

To remove O(a) errors by using Symanzik’s program, we must find all possible dimension-6 terms which are scalars under the lattice symmetry transformations. Then, we add them to the original action and adjust their coefficients so that low-momentum physical quantities do not have O(a) errors. When he proposed this program, Symanzik applied it to scalar fields and proved the consistency of the i...

We describe how the improvement of quark bilinears generalizes from quenched to unquenched QCD, and discuss which of the additional improvement constants can be determined using Ward Identities. A major motivation for undertaking the improvement program is to facilitate unquenched calculations by allowing simulations at larger lattice spacings. Thus it is important to study the application of t...

The potential between static-light mesons forming a meson-meson or a meson-antimeson system is calculated in quenched and unquenched SU(3) gauge theory. We use the Sheikholeslami-Wohlert action and statistical estimators of light quark propagators with maximal variance reduction. The dependence of the potentials on the light quark spin and isospin and the effect of meson exchange is investigate...

In order to understand the binding of four static quarks, flux distributions corresponding to these binding energies are studied in quenched SU(2) and also related to a model for the energies. The potential relevant to string breaking between two heavy-light mesons is measured in quenched SU(3) using stochastic estimates of light quark propagators with the Sheikholeslami-Wohlert action. Our goa...

We describe how the improvement of quark bilinears generalizes from quenched to unquenched QCD, and discuss which of the additional improvement constants can be determined using Ward Identities. A major motivation for undertaking the improvement program is to facilitate unquenched calculations by allowing simulations at larger lattice spacings. Thus it is important to study the application of t...

Div-salaar K1, Saravani R2, Shamsi-e-meimandi M3, Taei M4, Sheikholeslami A5 1. MSc. Staff member of Neurology Sciences Research Center, Kerman University of Medical Sciences 2. Instructor, Department of Biochemistry, Faculty of Medicine, Zahedan University of Medical Sciences 3. Instructor, Department of Physiology and Pharmacology, Faculty of Medicine, Neurology Sciences Research Center, Karm...