Narrow Results

We suggest that the dark matter halo in some of the spiral galaxies can be described as the ground state of the Bose–Einstein condensate of ultra-light self-gravitating axions. We have also developed an effective “dissipative” algorithm for the solution of nonlinear integro-differential Schrödinger equation describing self-gravitating Bose–Einstein condensate. The mass of an ultra-light axion is estimated.

We consider a two-component dark matter halo (DMH) of a galaxy containing ultra-light axions (ULA) of different mass. The DMH is described as a Bose–Einstein condensate (BEC) in its ground state. In the mean-field (MF) limit, we have derived the integro-differential equations for the spherically symmetrical wave functions of the two DMH components. We studied, numerically, the radial distribution of the mass density of ULA and constructed the parameters which could be used to distinguish between the two- and one-component DMH. We also discuss an interesting connection between the BEC ground state of a one-component DMH and Black Hole temperature and entropy, and Unruh temperature.

The elastic scattering cross-sections of ${}^{28}$Si projectile by ${}^{27}$Al, ${}^{28}$Si, ${}^{58}$Ni, ${}^{64}$Ni and ${}^{208}$Pb targets are analyzed using the double folding model based on the effective M3Y interaction which is known as the most popular density independent form. In the calculations of the double folding model, 16 different density distributions of ${}^{28}$Si nucleus are examined. A very good agreement between experimental data and theoretical results is obtained, and also the literature results support our results. In addition, dependence on incident energy, target atomic number and target mass number of the imaginary potential depth is studied, and new and global equations are proposed.

The effect of channel width on the density structure of confined fluid in the nano-/micro-channels is examined by equilibrium molecular dynamics (EMD) simulation. It was found that the density oscillation occurs near the wall in both cases of the macroscale or nanoscale confined flow. There exists a threshold channel width L_threshold, when channel width H<L_threshold, density oscillates throughout the channel. When H>L_threshold, L_threshold is constant and about 5–6 molecular diameter long, and the density becomes uniform beyond this threshold layer. A newly defined ch number may serve to be the parameter to compare similarity in the micro-/nano-scale channel flow. Moreover, the effect of the density oscillation on fluid mass flux rate is examined quantitatively. The result shows that the effect should be considered when the channel width is below 5 molecular diameter.

Calculations of the ^6,8He+²⁸Si total reaction cross-sections at intermediate energies are performed on the basis of the Glauber–Sitenko microscopic optical-limit model. The target-nucleus density distribution is taken from the electron-nucleus scattering data, and the ^6,8He densities are used as they are derived in different models. The results of the calculations are compared with existing experimental data. The effects of the density tails of the projectile nuclei as well as the role of shell admixtures and short-range correlations are analyzed.

We will study fermionic systems like atomic nuclei and bosonic systems like the correlated atoms in a trap from an information-theoretical point of view. The Shannon and Onicescu information measures are calculated for the above systems by comparing the correlated and uncorrelated cases as functions of the strength of the short range correlations. One-body and two-body density and momentum distributions are employed. Thus, the effect of short-range correlations on the information content is evaluated. The magnitude of distinguishability between the correlated and uncorrelated densities is also discussed employing suitable measures for the distance of states i.e. the well known Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. We will see that the same information-theoretical properties hold for quantum many-body systems obeying Bose–Einstein and Fermi–Dirac (statistics).

We calculate the ground state properties of recently synthesized superheavy elements (SHEs) from Z = 105–118 along with the predicted proton magic Z = 120. The relativistic and nonrelativistic mean field formalisms are used to evaluate the binding energy (BE), charge radius, quadrupole deformation parameter and the density distribution of nucleons. We analyzed the stability of the nuclei based on BE and neutron to proton ratio. We also studied the bubble structure which reveals the special features of the superheavy nuclei.

We have measured the angular distributions for ¹⁶O elastically scattered on ¹²C nuclei at energy 28 MeV and also for ¹²C ion beam elastically scattered on ¹¹B target nuclei at energy 18 MeV. These measurements were performed in the cyclotron DC-60 INP NNC RK. Calculations were performed using both empirical Woods–Saxon and double folding optical model potentials. Both elastic scattering and transfer reaction were taken into consideration. We have extracted the spectroscopic factors for the configurations ¹⁶O → ¹²C + α and ¹²C → ¹¹B + p and compared them with other calculated or extracted values at different energies from literature. The extracted spectroscopic factor for the configuration ¹²C → ¹¹B + p from the current work is in the range 2.7–3.1, which is very close to Cohen–Kurath prediction. While for the configuration ¹⁶O → ¹²C + α, spectroscopic factors show fluctuation with energy which could be due to the well-known resonant-like behavior observed in ¹⁶O + ¹²C excitation function.

In the present study, two different density distributions of oxygen isotopes (${}^{16\text{–}18}$O) that consist of the harmonic oscillator single-particle wave functions (SDHO) and the relativistic mean-field (RMF) approaches are investigated for the availability of elastic scattering cross-sections. For this purpose, the elastic scattering angular distributions of nuclear reactions with 13 target nuclei, four target nuclei and nine target nuclei are calculated for ${}^{16}$O, ${}^{17}$O and ${}^{18}$O, respectively. For these calculations, the double folding model based on the optical model is used. The optical potential parameters, volume integrals and cross-sections for all the nuclear reactions are given in this study. The comparison of theoretical results and experimental data shows very good agreement. The imaginary potential depth expressions, which will be new and more practical terms to explain the nuclear interactions of ${}^{16}$O, ${}^{17}$O and ${}^{18}$O with different nuclei, for each oxygen isotope are proposed.

The deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) has been proved as one of the best models to probe the exotic structures in deformed nuclei. In DRHBc, the potentials and densities are expressed in terms of the multipole expansion with Legendre polynomials, the dependence on which has only been touched for light nuclei so far. In this paper, taking a light nucleus ${}^{20}$Ne and a heavy nucleus ${}^{242}$U as examples, we investigated the dependence on the multipole expansion of the potentials and densities in DRHBc. It is shown that the total energy converges well with the expansion truncation both in the absence of and presence of the pairing correlation, either in the ground state or at a constrained quadrupole deformation. It is found that to reach the same accuracy of the total energy, even to the same relative accuracy by percent, a larger truncation is required by a heavy nucleus than a light one. The dependence of the total energy on the truncation increases with deformation. By decompositions of the neutron density distribution, it is shown that a higher-order component has a smaller contribution. With the increase of deformation, the high-order components get larger, while at the same deformation, the high-order components of a heavy nucleus play a more important role than that of a light one.

In this study, a systematic analysis is made on the ${}^{22}$Ne nucleus. First, using different theoretical approaches, we show eight density distributions for the ${}^{22}$Ne nucleus. For there densities, we obtain the elastic scattering angular distributions of ${}^{22}$Ne by ${}^{12}$C and ${}^{13}$C targets. Then, to offer alternative nuclear potentials in explaining nuclear interactions related to ${}^{22}$Ne projectile, we calculate the elastic scattering cross-sections of ${}^{22}\mathrm{\text{Ne}}+{}^{12}$C and ${}^{22}\mathrm{\text{Ne}}+{}^{13}$C reactions by using six different nuclear potentials. Finally, we investigate cluster structures of the ${}^{22}$Ne nucleus via a simple cluster approach. We compare the calculated elastic scattering angular distributions with the experimental data.

Quantifying differences in joint loading for coxa vara and coxa valga is important for understanding what constitutes a pathological deformity. Prior free-body analyses for varus and valgus femora suggest that the loading direction in single-leg stance becomes more vertical for coxa valga and more horizontal for coxa vara. The objectives of this study were: 1) to apply a density-based load estimation technique to varus and valgus femora; 2) to infer potential differences in femoral loading for varus and valgus femora from the density; and 3) to compare the results with previous studies of femoral loading for single-leg stance. Representative valgus, normal, and varus femora from male cadavers were scanned in the plane of the femoral neck using computed tomography. A two-dimensional finite element model, including the density data from the CT scans, was constructed for each femur. A density-based bone load estimation method was used to determine the dominant loading pattern, and an average load direction was calculated. The average load direction varied consistently from more vertical for coxa valga to more horizontal for coxa vara. The results indicate that the differences in loading directions reduce the risk of epiphyseal slip or neck fracture in coxa vara and increase the tendency for subluxation or dislocation in coxa valga. Agreement between relative load angles from the density-based load estimation and free-body analyses confirms that internal femoral density is adapted to applied loads regardless of external femoral geometry.