Related papers: Modified instanton profile effects from lattice Gr…
The infrared behaviour of QCD Green's functions in Landau gauge has been focus of intense study. Different non-perturbative approaches lead to a prediction in line with the conditions for confinement in local quantum field theory as spelled…
The infrared behavior of Yang-Mills theory at finite temperature provides access to the role of confinement. In this review recent results on this topic from lattice calculations and especially Dyson-Schwinger studies are discussed. These…
By use of single instanton approximation the twist-3 light-cone distribution amplitudes of pion as well as the p-wave mesons, i.e., $f_{0}(1370)$, $K_{0}^{\ast}(1430)$ and $a_{0}(1450)$ are investigated within the framework of QCD moment…
In this letter we argue that instanton-dominated Green's functions in N=2 Super Yang-Mills theories can be equivalently computed either using the so-called constrained instanton method or making reference to the topological twisted version…
For the gluon propagator of pure SU(2) lattice gauge theory in the Landau gauge we investigate the effect of Gribov copies and finite-volume effects. Concerning gauge fixing, we enlarge the accessible gauge orbits by adding non-periodic…
The Green-function technique, termed the irreducible Green functions (IGF) method, that is a certain reformulation of the equation-of motion method for double-time temperature dependent Green functions is presented. This method was…
We extend the covariant variational approach for SU(N) Yang-Mills theory in Landau gauge to non-zero temperatures. The renormalization of the zero-temperature case is revisited and it is shown that the same counterterms are sufficient to…
Flexible boundary condition methods couple an isolated defect to a harmonically responding medium through the bulk lattice Green's function; in the case of an interface, interfacial lattice Green's functions. We present a method to compute…
We describe the properties of instantons in lattice gauge theory when the action is a fixed point action of some renormalization group transformation. We present a theoretically consistent method for measuring topological charge using an…
We calculate the instanton-anti-instanton action $S_{M {\bar M}} (\tau)$ in the gauge theory of the half-filled Landau level. It is found that $S_{M {\bar M}} (\tau) = (3 - \eta) \left [ \Omega_0 (\eta) \ \tau \right ]^{1 / (3 - \eta)}$ for…
We study the instanton effect on the gluon scattering amplitudes at strong coupling and large $N$ for the ${\cal N}=4$ supersymmetric Yang-Mills theory. According to Alday and Maldacena, the gluon scattering amplitude corresponds…
We study the gluon sector in pure Yang-Mills theories via the computation of two, three and four point Landau gauge gluon correlation functions via LQCD using the Wilson action for Monte-Carlo simulations. The first goal was to use lattice…
The influence of nonperturbative fields on instantons in quantum chromodynamics is studied. Nonperturbative vacuum is described in terms of nonlocal gauge invariant vacuum averages of gluon field strength. Effective action for instanton is…
The SU(4)-instanton equations are natural BPS equations for instantons on 8-manifolds. We study these equations on nearly Kaehler and Calabi-Yau torsion manifolds of the form M x G/H, with G/H a coset space and M a product of a torus with…
We present a self-consistent calculation of the four-gluon vertex of Landau gauge Yang--Mills theory from a truncated Dyson--Schwinger equation. The equation contains the leading diagrams in the ultraviolet and is solved using as the only…
We estimate the instanton-induced vacuum energy in non-commutative U(1) Yang-Mills theory in four dimensions. In the dilute gas approximation, it is found to be plagued by infrared divergences, as a result of UV/IR mixing.
The finite-temperature behavior of gluon and of Faddeev-Popov-ghost propagators is investigated for pure SU(2) Yang-Mills theory in Landau gauge. We present nonperturbative results, obtained using lattice simulations and Dyson-Schwinger…
In the present work we consider the influence on the heavy quark correlators due to the instanton background in the framework of instanton liquid model (ILM) of QCD vacuum by taking into account also the perturbative gluon effects. For a…
We report on recent numerical computations of the Landau gauge gluon and ghost propagators as well as of the ghost-gluon vertex function in pure SU(3) Yang-Mills theory and in full QCD on the lattice. Special emphasis is paid to the low…
We evaluate the longitudinal or (chromo-)electric Yang-Mills gluon propagator in the recently proposed center-symmetric Landau gauge at finite temperature [1]. To model the effect of the Gribov copies in the infrared, we use the…