The operator method of the approximate solution of the Schrödinger equation

Operator method in solving non-linear equations of the Hartree-Fock type

“…The operator method (OM) of the approximate solution of the Schrödinger equation was suggested in the works of Feranchuk and Komarov [1][2][3]. In agreement with the results obtained in these and subsequent works (see, for example, refs.…”

A High-Precision Study of Anharmonic-Oscillator Spectra

“…Feranchuk et al [70,10] and Ferna ndez et al [71] also start with a rescaling transformation of the sort discussed in Section 2. They develop perturbation expansions, of both Rayleigh Schro dinger and Brillioun Wigner types.…”

Self-similar structures and fractal transforms in approximation theory

“…Several years after Ref. [10], there appeared a series of papers [23][24][25][26][27][28] advertizing the same idea of introducing control functions for rendering perturbation theory convergent. Nowdays the optimized perturbation theory is widely used for various problems, being employed under different guises and called by different names, such as modified perturbation theory, renormalized perturbation theory, variational perturbation theory, controlled perturbation theory, self-consistent perturbation theory, oscillatorrepresentation method, delta expansion, optimized expansion, nonperturbative expansion, and so on [23][24][25][26][27][28][29][30][31][32].…”