A machine learning approach to extrapolation of the ab initio no-core shell model (NCSM) [1] results to the infinite model space has been suggested in Ref. [2]. We modified this approach in Refs. [3,4] and proposed training an ensemble of artificial neural networks (ANN) with different topology and formulated selection rules both for the NCSM results used for the training and for the trained...
The $J$-matrix formalism in the oscillator basis, known also as the HORSE (Harmonic oscillator representation for scattering equations) [1] formlism, is used for calculations of elastic scattering, nuclear resonant states and reactions. Within the HORSE, the tridiagonal infinite kinetic energy matrix is fully taken into account, ensuring the correct asymptotic behavior of the wave function,...
Подход SS-HORSE [1], позволяющий описывать состояния непрерывного спектра на основе расчётов ab initio в модели оболочек без инертного кора (англ. No-Core Shell Model, NCSM) [2], был использован для определения положения полюса $S$-матрицы, со-ответствующего связанному состоянию ядра ${}^6$He в закрытом канале распада на три фраг-мента (ядро ${}^4$He и два нейтрона). Определение положения...
The properties of rare gas dimers are investigated. The spectrum of the neon dimer is computed by solving a differential equation, and the results are compared with existing theoretical data obtained using alternative approaches.
We investigate the breakup of $^{11}$Be halo nuclei on a light ($^{12}$C) and heavy ($^{208}$Pb) targets from intermediate (67 MeV/nucleon) to low (5-30 MeV/nucleon) energies within non-perturbative quantum-quasiclassical approach, in which the three dimensional time-dependent Schrödinger equation for halo nucleon was integrated simultaneously with the classical Hamiltonian equations...
Van der Waals molecules at ultralow energies are of significant interest in both experimental and theoretical research [1]. The ability to control the scattering length in ultracold gases makes these systems ideal for studying Efimov physics experimentally. Following the first successful observation of Efimov states in an ultracold cesium gas [2], numerous experimental studies have reported...
Deviation of the cross section for the nuclear reaction X(a, b)Y from the Gamow formula due to an interaction additional to the Coulomb one in the entrance channel has been analyzed. It is shown that the reaction cross section has an oscillating structure at low energies. If the maximum of the first oscillation is close to the threshold of the channel a+X, it has a resonance behavior. To...
Рассмотрена задача рассеяния заряженной частицы на двухчастичной системе-мишени, связанной притягивающим кулоновским взаимодействием. Хотя основной вклад в асимптотику волновой функции и ее компонент вносит асимптотическое кулоновское взаимодействие между двухчастичной мишенью и налетающей частицей, следующие дальнодействующие члены мультипольного разложения этого взаимодействия играют важную...
The Gailitis-Damburg (GD) oscillations are the near threshold singularities of cross-sections of reactive scattering predicted to exist in atomic systems [1, 2, 3]. They are the infinite series of logarithmically spaced maxima and minima of cross-section that can arise above the threshold of excited state of an atom due to the induced dipole interaction between the atom and the spectator...
Study of short-range correlations (SRC) of nucleons is very relevant in nuclear physics. One of the main problems within it is an isospin dependence of SRC showing an essential domination of np over pp or nn correlated pairs. At the same time, a quantitative description of high-momentum components of the distributions for spin-singlet pairs is complicated due to the absence of bound states in...
We consider the lattice Schr\"odinger operator $H_{\gamma \lambda \mu}(K)$ associated with a system of two identical particles on the two-dimensional square lattice $\mathbb{Z}^2$. It is assumed that the center-of-mass quasimomentum $K$ equals zero and that the particles may interact with each other either on-site or on the first and second nearest neighbouring sites in the lattice. These...
