مجله فیزیک کاربردی
سال دهم شماره 1 (پیاپی 20، بهار 1399)

In this work, we study entanglement dynamics in a two-qutrit systemunder the XX Hamiltonian, in the presence of Dzyaloshinskii-Moriya interaction and external magnetic field. Using the generalized concurrence as an entanglement measure, their entanglement dynamics are investigated by numerical computation and the appropriate graphs as a function of the parameters are depicted. The generalized concurrence measure changes for different values of interaction and non-phase coherence parameters can be investigated. It is observed that the entanglement dynamics variations range of these states is changed between maximum entanglement or no entanglement in qutrit systems, depending on the choice of the parameters involved.

Isolation of radiation sources is one of the most important methods of the radiation protection in order to prevent harm to human beings. Usually, lead cells with plumbic brick walls are used for isolation of medium and low radiation level sources. In this research, the maximum permissible activity of 60Co line source was calculated using both the analytical and Monte Carlo methods, such that the handling of this amount of activity inside the lead cell with 5 cm standard plumbic brick walls, could fulfill the accepted international criteria for lead cells application in restricted areas. The difference between the analytical and Monte Carlo results was obtained less than 16% in average. The results showed that, the activity of 60Co source should be less than 5.61 and 48.25 mCi for the analytical method and less than 6.67 and 56.36 mCi for Monte Carlo method respectively at irradiate/storage and load/unload (as well as transient) operation modes. The proposed analytical method could generate MCNPX code data with relatively good approximation.

Plasmonic production of the nanoparticles is an interesting field of research. A significant part of the plasmonic nanoparticle generation process is based on the creation of the nanobubbles by pulsed laser irradiation in the liquid medium.  Here, the generation of Ag nanoparticles produced in vicinity of the nanobubbles created by pulsed femtosecond laser is investigated. This investigation is performed on theoretical and computer simulation procedures. Our simulation in comparison with empirical results in previous reports has an acceptable agreement. We investigate the parameters such as: relationship between specific heat of the nanoparticles and temperature, variation of the nanoparticles’ volume expansion with the laser fluence, the temperature dependence of the nanoparticle average size and the ratio of nanoparticle/nanobubble volume versus the laser fluences. In the simulation we utilize the equations with spherical symmetry, the separation of the time and space parts and eventually solve the coupled equations in the Laplace space.

In this paper, using the first-principle procedure, the effective Hubbard parameters of La and Ru atoms are calculated. Then, the structural, electronic and thermodynamic properties of LaRuSi nano-layer using the density functional theory are investigated in the presence of spin-orbit coupling making use of Wien2k code. The generalized gradient approximation (GGA) and generalized gradient approximation plus Hubbard parameter (GGA+U) are used for exchange-correlation potential. The calculated results show that this nano-layer is a non-magnetic metal. The electron densities of states (DOS) show that the major contribution in DOS around the Fermi energy comes from d orbital of Ru surface atom. The calculated results of the linear coefficient of specific heat of electrons show that the contribution of the Ru atom located on the nano-layer surface is higher than the Ru atom located on the central layer. The thermodynamic properties of this nano-layer such as bulk modulus, Debye temperature, specific heat at constant pressure and volume and thermal expansion coefficient are calculated using quasi-harmonic Debye model at 0 K to 1000 K temperatures and 0 GPa to 10 GPa pressures. The specific heat at constant volume at low temperature is cubically dependent on temperature and at high temperatures, it reaches the classical constant limit 74 (J/molK).

The optical properties of aluminum-doped zinc oxide (AZO) and tin-doped indium oxide (ITO) thin films on glass and the flexible polymer substrate (PET) are studied and are compared. The purpose of this study is to obtain optimal layers with a minimum specific resistance and a clear transparency in the visible area. In the AZO and ITO coatings, two anti-reflective coatings for different applications are designed to increase transmission by the MacLeod coating software. For the two coating types, the highest transmission through the visible area (400 to 700 nm) was 98.01% and 95.41% for the AZO coatings and 81.85% and 79.45% for the ITO coatings. Also, by changing the substrate from glass to PET for the single layer of AZO and ITO, the average percentage of light transmission increased, and the rate of change in light transmission per wavelength was decreased. For two types of anti-reflective coatings of AZO and ITO layers, by changing the substrate from glass to PET, the highest transmission in the visible area (400 to 700 nm) was to 97.87 and 96.18% for AZO coatings and 82.23% and 80.04% for ITO coatings.

In this work, we have analytically calculated the energy spectrum of electrons and holes of quantum wires with V-shaped cross-sections and variable widths. To modify the wire structure, we have used the equations proposed by Inoshita et al. We introduce a new effective potential according to the shape of the cross-section of this nanowire for solving the Schrodinger equation. Using this proposed effective potential and considering a suitable modified coordinate (mapping coordinate) that enables us to separate two-dimensional wave functions into two one-dimensional equations. we have calculated the wave functions and corresponding eigenvalues of the charge carriers in these nanowires. We find that by increasing the curvature of the top of the quantum wire (b) the energy of the charge carriers will be decreased. Our results are in good agreement with previous research. The results of this work are valuable for studying the physical properties of V-shaped nanowires that require analytical computation.