Abstract

Abstract
Noncommutative features are introduced into a relativistic quantum field theory model of nuclear matter, the quantum hadrodynamics-I nuclear model (QHD-I). It is shown that the nuclear matter equation of state (NMEoS) depends on the fundamental momentum scale, eta, introduced by the phase-space noncommutativity (NC). Although it is found that NC geometry does not affect the nucleon fields up to O(eta(2)), it affects the energy density, the pressure and other derivable quantities of the NMEoS, such as the nucleon effective mass. Under the conditions of saturation of the symmetric NM under consideration, the estimated value for the noncommutative parameter is root eta approximate to 0.12 MeV/c.

Abstract
The nucleon single-particle energies (SPEs) of the selected nuclei, that is, O-16, Ca-40, and Ni-56, are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest-order constrained variational (LOCV) calculations for the symmetric nuclear matter with the Av(18) phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing aHartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-bodymomentumdistribution functions of nucleons, n(k, rho), with theHeaviside functions, the role of n(k, rho) in the nucleon SPEs at the major levels of the selected closed shell nuclei is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterizedWood-Saxon potential and the Av(18) density-dependent mean field potential which is constructed by the LOCV method. Considering the pointlike protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including n(k, rho), instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.

Abstract
The present work evaluates the effect of gap in the density-dependent one-body momentum distribution, n(k, rho), at the Fermi surface on the calculation of the single-particle properties of nucleons, i.e., the momentum- and density-dependent single-particle potential and the nucleon effective mass, and also on the calculation of the ground-state binding energy of the selected closed-shell nuclei, i.e., O-16, Ca-40, and Ni-56. In order to do this, n(k, rho) is constructed by use of the calculations of the lowest-order constrained variational method for the symmetric nuclear matter with the Av(18) potential up to J(max) = 2 and 5. It is shown that the gap in n(k, rho) at the Fermi surface has no significant effect on the calculation of single-particle properties in the case of J(max) = 5. In the relevant evaluation of the ground-state binding energy of selected nuclei, it is seen that the binding energy of O-16, improved by including n(k, rho), is closer to the experimental data, contrary to Ca-40 and Ni-56.

Abstract
An ungravity-inspired model is employed to examine the astrophysical parameters of white dwarf stars (WDs) using polytropic and degenerate gas approaches. Based on the observed properties such as mass, radius, and luminosity of selected WDs, namely, Sirius B and epsilon Reticulum, bounds on the characteristic length and scaling dimension of the ungravity (UG) model are estimated. The UG effect on the Chandrasekhar limit for WDs is shown. The UG model is examined in the study of ultramassive WDs, e.g., EUVE J1746-706. The UG-inspired model implies that a new location for some WDs on the Hertzsprung-Russell diagram is found.

Abstract
We study neutron stars (NSs) in an ungravity (UG) inspired model. We examine the UG effects on tlie static properties of the selected NSs, in different mass and radius regimes, i.e., ultralow, moderate, and ultrahigh mass NSs, using a polytropic equation of state approach. Based on the observational data, we obtain bounds on the characteristic length and scaling dimension of the UG model. Furthermore, we obtain dynamic properties, such as inertial moment (I), Love number (Love), and quadrupole moment (Q) of a slowly rotating NS in the presence of the exterior gravity and ungravity fields. The UG model is also examined with respect to the I-Love-Q universal relation.