Accomplished Research |
Locating quantum resonances was always a difficult problem in quantum
mechanics. It is well-known that resonances are associated with zeros
of the Jost function in the complex momentum plane. Almost any
textbook on the scattering theory has a chapter devoted to the Jost
function, but none of them gives a practical recipe for its
calculation. Thus one usually gets a feeling that Jost function is a
pure mathematical entity, elegant and useful in formal theory, but
impractical in computations. In practice, therefore, resonances are
located by various very complicated expansion methods.
During last few years we developed an exact and practical method for direct calculation of the Jost function for all complex momenta of physical interest, including the spectral points corresponding to bound and resonant states. The method proved to be valid also for complex values of the angular momentum, which enables us to locate the Regge trajectories as well. It is shown, by using several examples, that highly accurate results can be obtained for extremely wide as well as for extremely narrow resonances with or without the presence of the Coulomb interaction and for noncentral potentials which couple states of different angular momenta. The method is also extended to multichannel problems, singular potentials, and to the class of few-body problems which can be treated within the hyperspherical approach. This extention enabled us to locate the subthreshold resonances in the three- and four-neutron systems, namely, E(nnn)= ![]() ![]() Currently, I am developing a method based on the Jost functions, for locating quantum resonances in semiconductor nanostructures. |
The production of ![]() ![]() ![]() ![]() ![]() In our papers published during the last five years, we presented the first microscopic calculations concerning the low-energy scattering of ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
During a short period of cosmic history, between about 10 and 500
seconds after the Big Bang, the primordial abundances of light
elements were formed via the ![]() ![]() We performed (for the first time) a microscopic analysis of several nuclear reactions not included into the standard model of the ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
The difficulties associated with the space charge of the particle beam in an accelerator, grow rapidly when the current carried by the beam increases. Dealing with an electron accelerator with the pulse current of 200A, we tried to keep the flow of electrons as close to laminar one as possible. To this end we designed a source of electrons (electron gun) with a special geometry and the optical system with minimal disturbance of the laminar flow. With beams of high intensity instabilities caused by its coherent oscillations significantly limit the length to which the beam can be transported through the optical system. We developed a new stochastic method for analyzing the tolerances within which this system may deviate from axial symmetry. |