Semiclassical quantization with bifurcating orbits

Bifurcations of classical orbits introduce divergences into semiclassical spectra which have to be smoothed with the help of uniform approximations. We develop a technique to extract individual energy levels from semiclassical spectra involving uniform approximations. As a prototype example, the method is shown to yield excellent results for photo-absorption spectra for the hydrogen atom in an electric field in a spectral range where the abundance of bifurcations would render the standard closed-orbit formula without uniform approximations useless. Our method immediately applies to semiclassical trace formulae as well as closed-orbit theory and offers a general technique for the semiclassical quantization of arbitrary systems

The hydrogen atom in an electric field: Closed-orbit theory with bifurcating orbits

Closed-orbit theory provides a general approach to the semiclassical description of photo-absorption spectra of arbitrary atoms in external fields, the simplest of which is the hydrogen atom in an electric field. Yet, despite its apparent simplicity, a semiclassical quantization of this system by means of closed-orbit theory has not been achieved so far. It is the aim of this paper to close that gap. We first present a detailed analytic study of the closed classical orbits and their bifurcations. We then derive a simple form of the uniform semiclassical approximation for the bifurcations that is suitable for an inclusion into a closed-orbit summation. By means of a generalized version of the semiclassical quantization by harmonic inversion, we succeed in calculating high-quality semiclassical spectra for the hydrogen atom in an electric field

Ballistic matter waves with angular momentum: Exact solutions and applications

An alternative description of quantum scattering processes rests on inhomogeneous terms amended to the Schroedinger equation. We detail the structure of sources that give rise to multipole scattering waves of definite angular momentum, and introduce pointlike multipole sources as their limiting case. Partial wave theory is recovered for freely propagating particles. We obtain novel results for ballistic scattering in an external uniform force field, where we provide analytical solutions for both the scattering waves and the integrated particle flux. Our theory directly applies to p-wave photodetachment in an electric field. Furthermore, illustrating the effects of extended sources, we predict some properties of vortex-bearing atom laser beams outcoupled from a rotating Bose-Einstein condensate under the influence of gravity.Comment: 42 pages, 8 figures, extended version including photodetachment and semiclassical theor

СОВЕРШЕНСТВОВАНИЕ КОМБИНИРОВАННОЙ ТЕХНОЛОГИИ РЕГЕНЕРАЦИИ ФИЛЬТРОВ ВОДОЗАБОРНЫХ СКВАЖИН

The paper presents an experience concerning application of a combined technology for restoration of water-well discharge. The technology includes consists of a step-by-step filter treatment by hydrogen explosions, a reagent and low-frequency waves.A diagram of the developed equipment for reagent treatment and efficiency pertaining to execution of works at water-wells are given in the paper.Технология включает последовательную обработку фильтра взрывами водорода, реагентом и низкочастотными волнами.Представлена схема разработанного оборудования для реагентной обработки и эффективности проведения работ на скважинах

ЛАБОРАТОРНЫЕ ИССЛЕДОВАНИЯ ПО ОЦЕНКЕ ЭФФЕКТИВНОСТИ ДЕКОЛЬМАТАЦИИ ФИЛЬТРОВ СКВАЖИН

Results pertaining to efficiency evaluation of well screen regeneration using a combined impulse and reagent method is given in the paper. In order to ensure complete cleaning of screen fragment from sedimentation a gas and dynamic set without and with pneumatic packers has been applied. After  gas and dynamic regeneration a part of the screen with sedimentation has been subjected to a reagent treatment while using hydrochloric acid and «Descam» reagent.The combined method for well screen regeneration is considered as the most efficient one and this fact is proved by laboratory experiments.Приводятся результаты оценки эффективности декольматации фильтра скважины комбинированным импульсно-реагентным методом. Для этого с целью более полной очистки фрагмента фильтра от кольматирующих отложений применялась газодинамическая установка без пакеров и с пневматическими пакерами. После газоимпульсной декольматации проводилась реагентная обработка части закольматированного фильтра с использованием соляной кислоты и реагента «Дескам».Комбинированный метод декольматации фильтров скважин является наиболее эффективным, что подтверждается лабораторными экспериментами

IMPROVEMENT OF COMBINED TECHNOLOGY FOR REGENERATION OF WATER-WELL FILTERS

The paper presents an experience concerning application of a combined technology for restoration of water-well discharge. The technology includes consists of a step-by-step filter treatment by hydrogen explosions, a reagent and low-frequency waves.A diagram of the developed equipment for reagent treatment and efficiency pertaining to execution of works at water-wells are given in the paper

Amplitude estimation of signal with unknown duration

Quasilikelihood and maximum likelihood algorithms for estimating the amplitude of arbitrary waveform signal with unknown duration have been synthesized. Characteristics of the synthesized algorithms have been also found