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E. A. Kolganova

Publications and source records attributed to E. A. Kolganova.

35 records · Page 2Linked to original sources
arXiv2010

Solution of three-dimensional Faddeev equations: ultracold Helium trimer calculations with a public quantum three-body code

We present an illustration of using a quantum three-body code being prepared for public release. The code is based on iterative solving of the three-dimensional Faddeev equations. The code is easy to use and allows users to perform highly-accurate calculations of quantum three-body systems. The previously known results for He$_3$ ground state are well reproduced by the code.

physics.atm-clus↗
arXiv2003

Binding Energies and Scattering Observables in the ^3He^4He_2 Atomic System

The ^3He^4He_2 three-atomic system is studied on the basis of a hard-core version of the Faddeev differential equations. The binding energy of the ^3He^4He_2 trimer, scattering phase shifts, and the scattering length of a ^3He atom off a ^4He dimer are calculated using the LM2M2 and TTY He-He interatomic potentials.

physics.atm-clus↗
arXiv2003

The ^3He^4He_2$ trimer within the hard-core Faddeev approach

We apply a hard-core version of the Faddeev differential equations to the ^3He^4He_2 three-atomic system. Employing the TTY interatomic potential by Tang, Toennies and Yiu we calculate the binding energy of the ^3He^4He_2 trimer and the scattering length of a ^3He atom off a ^4He dimer.

physics.atm-clus↗
arXiv2000

Complex Scaling of the Faddeev Equations

In this work we compare two different approaches to calculation of the three-body resonances on the basis of Faddeev differential equations. The first one is the complex scaling approach. The second method is based on an immediate calculation of resonances as zeros of the three-body scattering matrix continued to the physical sheet.

physics.comp-ph↗
arXiv2000

Binding Energies and Scattering Observables in the 4Helium3 Atomic System

The 4He3 system is investigated using a hard-core version of the Faddeev differential equations and realistic 4He-4He interactions. We calculate the binding energies of the 4He trimer but concentrate in particular on scattering observables. The atom-diatom scattering lengths are calculated as well as the atom-diatom phase shifts for center of mass energies up to 2.45 mK.

physics.atm-clus↗
arXiv2000

Complex Scaling of the Faddeev Operator

The work is devoted to comparison of two different approaches to calculation of three-body resonances on the basis of the Faddeev differential equations. The first one is the well known complex scaling approach. The second method is based on an immediate calculation of the zeros of the scattering matrix continued to the physical sheet.

nucl-th↗
arXiv1999

Binding Energies and Scattering Observables in the 4^He_3 Atomic System

The ^4He_3 bound states and the scattering of a ^4He atom off a ^4He dimer at ultra-low energies are investigated using a hard-core version of the Faddeev differential equations. Various realistic ^4He-^4He interactions were employed, amomg them the LM2M2 potential by Aziz and Slaman and the recent TTY potential by Tang, Toennies and Yiu. The ground state and the excited (Efimov) state obtained are compared with other results. The scattering lengths and the atom-diatom phase shifts were calculated for center of mass energies up to 2.45 mK. It was found that the LM2M2 and TTY potentials, although of quite different structure, give practically the same bound-state and scattering results.

physics.atom-ph↗
arXiv1998

Scattering and resonances in the ^4He three-atomic system

A mechanism of disappearance and formation of the Efimov levels of the helium ^4He_3 trimer is studied when the force of interatomic interaction is changed. The resonances including virtual levels are calculated by the method based on the solving the boundary value problem, at complex energies, for the Faddeev differential equations describing the (2+1 --> 2+1; 1+1+1) scattering processes.

physics.atm-clus↗
arXiv1998

Three-Body Configuration Space Calculations with Hard Core Potentials

We present a mathematically rigorous method suitable for solving three-body bound state and scattering problems when the inter-particle interaction is of a hard-core nature. The proposed method is a variant of the Boundary Condition Model and it has been employed to calculate the binding energies for a system consisting of three ^4He atoms. Two realistic He-He interactions of Aziz and collaborators, have been used for this purpose. The results obtained compare favorably with those previously obtained by other methods. We further used the model to calculate, for the first time, the ultra-low energy scattering phase shifts. This study revealed that our method is ideally suited for three-body molecular calculations where the practically hard-core of the inter-atomic potential gives rise to strong numerical inaccuracies that make calculations for these molecules cumbersome.

physics.chem-ph↗
arXiv1998

On the mechanism of formation of the Efimov states in the helium ^4He trimer

A mechanism of disappearance and formation of the Efimov levels of the helium ^4He trimer is studied when the force of the interatomic interaction is changed. It is shown that these levels arise from virtual levels which are in turn formed from (quasi)resonances settled on the real axis. The resonances including virtual levels are calculated by the method based on the solution of the boundary value problem, at complex energies, for the Faddeev differential equations describing the scattering processes (2+1\to 2+1; 1+1+1). All the calculations are performed with the known interatomic Aziz He-He potential HFD-B. A very strong repulsive component of this potential at short distances between helium atoms is approximated by a hard core. A special attention is paid to the substantiation of the method used for computing resonances and to the investigation of its applicability range.

physics.atm-clus↗
arXiv1998

Using Faddeev Differential Equations to Calculate Three-Body Resonances

Algorithm, based on explicit representations for analytic continuation of the T-matrix Faddeev components on unphysical sheets, is worked out for calculations of resonances in the three-body quantum problem. According to the representations, poles of T-matrix, scattering matrix and Green function on unphysical sheets, interpreted as resonances, coincide with those complex energy values where appropriate truncations of the scattering matrix have zero as eigenvalue. Scattering amplitudes on the physical sheet, necessary to construct scattering matrix, are calculated on the basis of the Faddeev differential equations. The algorithm developed is applied to search for the resonances in the $nnp$ system and in a model three-boson system.

nucl-th↗
arXiv1998

Ultra-low energy scattering of a He atom off a He dimer

We present a new, mathematically rigorous, method suitable for bound state and scattering processes calculations for various three atomic or molecular systems where the underlying forces are of a hard-core nature. We employed this method to calculate the binding energies and the ultra-low energy scattering phase shifts below as well as above the break-up threshold for the three He-atom system. The method is proved to be highly successful and suitable for solving the three-body bound state and scattering problem in configuration space and thus it paves the way to study various three-atomic systems, and to calculate important quantities such as the cross-sections, recombination rates etc.

physics.chem-ph↗
arXiv1997

Bound States and Scattering Processes in the ^4He_3 Atomic System

We present a mathematically rigorous method for solving three-atomic bound state and scattering problems. The method is well suited for applications in systems where the inter-atomic interaction is of a hard-core nature. It has been employed to obtain the ground- and excited-state energies for the Helium trimer and to calculate, for the first time, the scattering phase shifts and wave-functions for the He atom-He dimer at ultra-low energies.

physics.chem-ph↗
arXiv1997

Three-Body Resonances in Framework of the Faddeev Configuration Space Approach

Algorithm, based on explicit representations for analytic continuation of the T-matrix Faddeev components on unphysical sheets, is worked out for calculations of resonances in the three-body quantum problem. According to the representations, poles of the T--matrix, scattering matrix and resolvent on unphysical sheets, interpreted as resonances, coincide with those complex energy values where appropriate truncations of the scattering matrix have zero as eigenvalue. Scattering amplitudes on the physical sheet, necessary to construct scattering matrix, are calculated on the basis of the Faddeev differential equations. Effectiveness of the algorithm developed is demonstrated for example of searching for resonances in the system $nnp$ and in a model three-boson system.

nucl-th↗