Related papers: Instanton effects on charmonium states
We extend the worldline instanton technique to compute the vacuum pair production rate for spatially inhomogeneous electric background fields, with the spatial inhomogeneity being genuinely two or three dimensional, both for the magnitude…
In this work a comprehensive analysis of the mass spectrum and decay properties of charmonium states within a relativistic framework is carried out. The present experimental status of charmonium states is reviewed. Utilizing a screened…
The charmonium system is studied in a Salpeter model with a vector plus scalar potential. We use a kinematical formalism based on the one developed by Suttorp, and present general eigenvalue equations and expressions for decay observables…
We study, in the multipolar coupling scheme, a uniformly accelerated multilevel hydrogen atom in interaction with the quantum electromagnetic field near a conducting boundary and separately calculate the contributions of the vacuum…
A technique is presented for treating strongly nonstationary and transient processes in optics, permitting one to take into account both types of competing with each other effects, quantum as well as coherent. The main equations for…
{(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 revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model…
A consistent treatment of the ground state correlations beyond the random phase approximation including their influence on the pairing and phonon-phonon coupling in nuclei is presented. A new general system of nonlinear equations for the…
Understanding the non-equilibrium dynamics of extended quantum systems after the trigger of a sudden, global perturbation (quench) represents a daunting challenge, especially in the presence of interactions. The main difficulties stem from…
The coefficients of the membrane instantons in the ABJM theory are known to be quadratic polynomials of the chemical potential. We show that, after deforming the ABJM theory into more general superconformal Chern-Simons theories labelled by…
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…
In this paper we apply the instanton representation method to the construction of spherically symmetric blackhole general relativity solutions. The instanton representation implies the existence of additional Type D solutions which are…
We investigate the ground-state energy of the integrable two dimensional $O(3)$ sigma model in a magnetic field. By determining a large number of perturbative coefficients we explore the closest singularities of the corresponding Borel…
We consider new instantons that appear as a result of accounting for quantum fluctuations. These fluctuations naturally regularize the O(4) singular solutions abandoned in Coleman's theory. In the previous works [3,4] we showed how new…
We examine the effect of a non-trivial nut charge on the action of non-compact four-dimensional instantons with a U(1) isometry. If the instanton action is calculated by dimensionally reducing along the isometry, then the nut charge is…
It is well known that the instanton approach to QCD generates an effective term which looks like a three flavor determinant of quark bilinears. This has the right behavior to explain the unusual mass and mixing of the $\eta(958)$ meson, as…
The gluon fields screening in the stochastic vacuum of gluodynamics is studied. The effective action is derived for the instanton interacting with nonperturbative fields. Quantum nonperturbative effects are shown to affect greatly the shape…
We present a method of measuring the quantum state of a harmonic oscillator through instantaneous probe-system selective interactions of the Jaynes-Cummings type. We prove that this scheme is robust to general decoherence mechanisms,…
In this chapter we give a pedagogical introduction to the constituent quark model. The explanation of magnetic moments of the nucleons was crucial to introduce an effective quark mass for light quarks that nowadays are understood as an…
The QCD + QED axial anomaly low-energy theorems are applied to estimate the accuracy of an instanton vacuum - based chiral quark model. The low-energy theorems give an exact relation between the matrix elements of the gluon and photon parts…