Related papers: Instanton size distribution: repulsion or the infr…
We consider aspects of instanton dynamics in the large-N limit using the AdS/CFT duality for D0/D4 bound states. In the supergravity picture of wrapped D0-brane world-lines on D4-branes, we find the single-instanton measure and discuss its…
Using the soft pion theorem, crossing, and the dispersion relations for the two pion distribution amplitude ($2\pi$DA) we argue that the second Gegenbauer moment the $\rho$-meson DA ($a_2^{(\rho)}$) most probably is negative. This result is…
Finite temperature instantons between meta-stable vacua of correlated electronic system are solved analytically for quasi one-dimensional Hubbard model. The instantons produce dynamic symmetry breaking and connect metallic state with the…
We study the topological content of the SU(3) vacuum using a method based on RG mapping developed for SU(2) gauge theory earlier. RG mapping, in which a series of APE-smearing steps is done while tracking the observables, reduces the short…
{(Anti-)instanton behaviour in Euclidean non-abelian field of the point-like source is studied by analyzing the possible (anti-)instanton deformations as resulted from the variations of its characteristic parameters. The variational…
We develop a cooling method controlled by a physical cooling radius that defines a scale below which fluctuations are smoothed out while leaving physics unchanged at all larger scales. We apply this method to study topological properties of…
We propose a practical empirical fitting function to characterize the non-Gaussian displacement distribution functions (DispD) often observed for heterogeneous diffusion problems. We first test this fitting function with the problem of a…
Numerical and anaytical studies of the instanton liquid model have allowed the determination of many hadronic parameters during the last 13 years. Most part of this thesis is devoted to the extension of the analytical methods. The meson…
The validity of the instanton analysis approach is tested numerically in the case of the diffraction-amplification problem $\partial_z\psi -\frac{i}{2m}\partial^2_{x^2} \psi =g\vert S\vert^2\, \psi$ for $\ln U\gg 1$, where…
We consider a system of interacting diffusions on the integer lattice. By letting the mesh size go to zero and by using a suitable scaling, we show that the system converges (in a strong sense) to a solution of the stochastic heat equation…
Inferring a diffusion equation from discretely-observed measurements is a statistical challenge of significant importance in a variety of fields, from single-molecule tracking in biophysical systems to modeling financial instruments.…
Instantons play a crucial role in understanding non-perturbative dynamics in quantum field theories, including those with spontaneously broken gauge symmetries. In the broken phase, finite-size instanton-like configurations are no longer…
We study instanton contributions to hadronic decays of the scalar glueball, the pseudoscalar charmonium state $\eta_c$, and the scalar charmonium state $\chi_c$. Hadronic decays of the $\eta_c$ are of particular interest. The three main…
It is shown that the inhomogeneous saddle points of scale invariant theories make the semiclassical expansion sensitive on the choice of non-renormalizable operators. In particular, the instanton fugacity and the beta function of the two…
A family of SO(10) symmetric instanton solutions in Type IIB supergravity is developed. The instanton of least action is a candidate for the low-energy, semiclassical approximation to the {D=--1} brane. Unlike a previously published…
We study the scaling behavior and finite (physical) volume effects as well as the Gribov copy dependence of the SU(2) Landau gauge gluon propagator on the lattice. Our physical lattice sizes range from $(3.0 \mathrm{fm})^4$ to $(7.3…
The Landau gauge gluon propagator for the pure gauge theory is evaluated on a 32^3x64 lattice with a physical volume of (3.35^3x6.7)fm^4. Comparison with two smaller lattices at different lattice spacings allows an assessment of finite…
The role of instanton-like objects in the QCD vacuum on the mass spectrum of low-lying light hadrons is explored in lattice QCD. Using over-improved stout-link smearing, tuned to preserve instanton-like objects in the QCD vacuum, the…
In this article we consider a path integral formulation of the Hubbard model based on a SU(2)-symmetrical Hubbard-Stratonovich transformation that couples auxiliary field to the local electronic density. This decoupling is known to have a…
We derive the semiclassical (instanton-induced) contribution to the inelastic cross section of two color dipoles at large $\sqrt{s}$. We study its dependence on the dipole sizes, orientations and, most importantly, the impact parameter. The…