We describe the generalization of Analytic Perturbation Theory (APT) for QCD observables, initiated by Radyushkin, Krasnikov, Pivovarov, Shirkov, and Solovtsov, to fractional powers of coupling — Fractional APT (FAPT). The ...
Using the explicit factorized formulas for matrix elements (formfactors) of the spin operators between the eigenvectors of the Hamiltonian of a finite quantum XY-chain in a transverse field, the spontaneous magnetization ...
The main stages of development of the theory of superconducting systems with overlapping energy bands are formulated. The main references of the classical papers of the author of this theory, Prof. V.A. Moskalenko, and his ...