JOURNAL OF RESEARCH ON MANY BODY SYSTEMS
Year:2018 | Volume:8 | Issue:18 |Papers Count:20

In the present work, to improve the knowledge of and interactions better, the existence possibility of a bound state for the double-hyperonic three-body system ( Lambda-Lambda-proton, Lambda-Lambda-neutron ) has investigated in the computational point of view. To study the structure of these three-body systems, Nijmegen group ND, NF, NS, ESC  models and Julich group JA, JB interactions, that coupling effect are explicitly considered for potential, and a pseudo-OBE model for interaction, have been used. Minimum energy value of system for the seven interaction models are obtained in range of 1.6 to 1.8 MeV and therefore no any bound state is found for these system.

In this research, four different magnetic Fe3O4 nanoparticles were synthesized and characterized by solvothermal method based on different sodium salts. To study effect of PAM coating on the uranium absorption, the synthesized magnetic Fe3O4 nanoparticles were coated with PAM (Fe3O4@PAM). The structural properties of the synthesized magnetic Fe3O4@PAM nanoparticles were examined by XRD, FT-IR and SEM. The XRD patterns indicated that the crystal structure of Fe3O4@PAM nanocomposites are remained the same structure as the Fe3O4 nanoparticles which have a respectable agreement with other valid experiments. As well as, The XRD and FT-IR results for Fe3O4@PAM nanoparticles showed that PAM coated on Fe3O4 successfully. The prepared Fe3O4 and Fe3O4@PAM nanoparticles were applied as sorbents to sorb uranium ions (U(VI)) from aqueous solution. In adsorption test the effect of pH were investigated. pH had significant effect on the amount of adsorption. The adsorption results showed that the highest U(VI) adsorption of 197 mg/g at around the solution pH 10 were obtained for Fe3O4 nanoparticels which synthesized based on Na2CO3; and 185 mg/g at around the solution pH 8 to 9 for Fe3O4@PAM nanoparticles which was based on a mixed sodium source involved the Sodium acetate and Trisodium citrate.

]In this paper has been simulated the temperature field and flows during different stages of low thermal gradient (LTG) Czochralski single crystal growth and using the resistive heating system has been simulated and the quality of grown crystal has been investigated using the thermal stress at the different heights has been investigated. The configuration of the used growth furnace in this system is in accordance with a real system in the lab and is consists of a cylindrical ceramic tube, a heat shield and three element heat zones with different radius to generate and control the low temperature gradient. The surface to surface and internal radiation heat transfer has been considered in system. The results of simulation and its adaptation to experimental data show that the low temperature gradient and specific configuration of the system leads to optimization of the crystal-melt interface, the reduction of thermal stresses and the improvement of the quality of the crystal grown.

Determining the amount of entanglement is one of the important subjects in the quantum information theory. In this field, different measures have been introduced to determine the degree of entanglement of bipartite systems. Concurrence and tangle measures are two samples of these measures, which are generally difficult to calculate analytically for arbitrary mixed states. Hence, in order to have an approximation of entanglement, besides of the numerical methods, a series of upper and lower bounds that can be easily calculated have been introduced. On the other hand, concurrence and tangle measures have a relationship, in certain range with Ré nyi entanglement measure. In this paper, using the upper and lower bounds of tangle and concurrence measures and with regard to the relationship between these measures and the Ré nyi entanglement measure, upper and lower bounds are introduced for the Ré nyi entanglement measure. Then, in a spin system, the efficiency of these bounds is examined.

Abstract: In this paper, the impact of electric and magnetic field effects on the electronic, linear and nonlinear optical properties of bound to continuum states transitions are investigated in a system of InAs/GaAs conical shaped quantum dot. The electronic structure, containing two main states of S and wetting layer states (WL), was calculated by solving one electronic band Hamiltonian with effective-mass approximation. In order to predict the optical properties of this model, transition dipole moment (TDM) for bound-to-continuum (P-to-WL) transition were studied. The results reveal that with increasing the electric and magnetic fields strength, the absorption and refractive index coefficients’ peaks increase. The physical reasons behind these interesting phenomena were also explained based on the electronic features of the z-polarized intersubband transition.

In this paper, we consider cluster of galaxy as many body system and study effect of dark energy with varying energy density on the thermodynamics and statistical mechanics of mentioned system. Some thermodynamics quantities calculated in the canonical ensemble such as Helmholtz free energy, entropy, and specific heat of the system, and also the second law of thermodynamics verified. Moreover, we obtain probability and distribution function in the grand canonical ensemble and study time evolution of galaxy clustering by graphical analysis. We compare our results with observations and many body simulations and show that our model agrees with Peebles power law for the correlation function.

In this paper, the effects of a relative position gamma source-scintillator on the efficiency of a large NE102 rectangular plastic scintillator (50 cm ×50 cm × 5 cm) have been simulated and measured. The response functions of the plastic scintillator at different 137Cs gamma source relative scintillator positions using MCNPX-PHOTRACK code have been simulated. The solid angle subtended by the detector at the location of the source for different situations has been analytically calculated, and the effects on the efficiency of changes in the solid angle as a function of distance between the source and detector have been identified. The comparison confirms that the simulated response function represents a promising agreement with experiments.

In this paper, The structural, electronic, optical and elastic properties of Heusler compounds Co2CrZ(Z=Al, Ga) have been studied. Calculations were performed using the Full-Potential-Linearized Argumented Plane Wave(FP-LAPW) method in the framework of density functional theory with GGA approximations by Wien2k computational code. In this research structural properties of Co2CrZ(Z=Al, Ga) such as lattice constants, bulk modulus and its derivative properties are investigated during structural calculations. The lattice constants used in the calculations are 5. 6787 (Å ) and 5. 7235(Å ) for and Co2CrGa compounds respectively. Moreover electronic properties such as bandstructure and density of states were investigated. and Co2CrGa compounds don’ t have any band gap at majority spin channel, but in minority chanel there is a small band gap by an amount 0. 4 (eV) and 0. 2 (eV) respectively so these compounds are half-mettals. Also we studied the elastic properties of these compounds and the results showed that have more elastic resistivity than Co2CrGa. Also optical properties revealed good agreement between density of states and imaginery part of dielectric function and the investigated static refractive index from real part of dielectric constants is about 10.

In this research, graphene oxide (GO) was mixed with Fe2O3 nanoparticles by using sonication with 10: 1 volume ratio. The nonlinear absorption of graphene oxide, Fe2O3 nanoparticles, and the mixture of GO-Fe2O3 were studied by using open aperture Z-scan method. Also the optical limiting of these materials were investigated. It was observed that the nonlinear absorption and optical limiting of graphene oxide has been increased when mixed with Fe2O3 nanoparticles. The light source that was used in all experiments was a continuous wave laser diode at 532 nm wavelength. In Fe2O3 nanoparticles a switch over from saturable absorption to reverse saturable absorption behavior with increasing the input intensity was observed. In GO and GO-Fe2O3 samples with increasing intensity the depth of vally in open aperture Z-scan curves increased and their nonlinear absorption coefficient rose to an optimal value. It was also observed that in GO-Fe2O3 mixture by increasing the length of sample, optical limiting power increased.

In this research, we study the correlations between magnetic monopoles and center vortices in SU(2) and SU(3) gauge groups in a phenomenological model. Both center vortices and monopoles lead to the quark confinement. Therefore, one may expect that there is some kind of relation between monopoles and center vortices. Investigating the quark potentials and group factor obtained by the monopole-antimonopole pairs in SU(2) gauge group, we observe that these pairs deform to monopole-vortex chains. The results agree with lattice gauge theory. In addition, we investigate combinations of magnetic monopoles in SU(3) gauge group leading to vortex flux.

In this research, thermopower properties of C20 fullerene molecule and the effect of increasing the number of molecule is investigated using density functional theory and Green’ s function formalism in linear response regime. We consider three different configuration: Au-C20-Au, Au-(C20)2-Au and finally Au-(C20)3 – Au. The calculation show that increasing the number of C20 fullerene molecules in the device increases the molecular thermopower. In addition, the signs of the seebeck coefficient are length dependent and can be positive (p type) or negative (n type) for different number of C20 fullerene molecules. Thermopower, increases the figure of merit in the system and will lead to more efficient thermoelectric Device.

In this paper, we study multilevel multi-photon resonances in a strongly driven four-level quantum system, where one level is periodically swept through other levels with constant energy separation E and 2E. Near the multi-photon resonance conditions, we find qualitatively different behavior for the number of even or odd photons. We explain this phenomenon in terms of families of interfering trajectories of the multilevel system. For beginning our detailed analysis based on a perturbative treatment in terms of the small parameters that characterize the strong driving limit, we introduce the strong-dephasing regime that is modeled by Gaussian white-noise fluctuations on each of the unperturbed energy levels. Within this model we calculate the rates of inter-level transitions, working up to fourth order in the couplings. Finally, we connect our results to the experiments in which current through spin-blockaded double quantum dots was measured in the presence of strong ac driving. The setup can be relevant for a variety of solid state and atomic or molecular systems. In particular, it provides a clear mechanism to explain recent puzzling experimental observations in strongly driven double quantum dots.

In this paper, the effects of initial temperature of ions on the expansion of a one-dimensional collisionles plasma into vacuum is studied using kinetic theory. The particle dynamics is determined by the Vlasov equation for the electrons and ions based on a simulation code. In this simulation code, the Vlasov equation is solved by the characteristics method. The initial temperature effects of ions with comparison of different temperature ratio ions per electrons (Ti/Te), is investigated in the simulation. The results show that, the increase in the temperature of the ions leads to the higher velocity of the ions which cause the proximity of ions to electrons and then the faster decrease of the electric field. In addition, due to the initial temperature of the ions, the rate of expansion of plasma will increase.

In this article, we present fabrication and characterization of two-layered polymer light emitting diode (PLED) with a structure of ITO/PEDOT: PSS/MEH: PPV/Al which emits a orange-colored light, with the aim of reduction of lightening voltage. In this work, the PEDOT: PSS layer, as hole injection layer, was coated with spin coating method and a rotating speed of 2000 rpm and the MEH: PPV layer, as an active layer (emission layer), was coated with four rotating speeds. The impact of change in layer thickness on the surface roughness, optical absorption, and most importantly, the lightening voltage was investigated. Eventually, a PLED with a structure of ITO/PEDO: PSS(2000 rpm)/MEH: PPV(6000 rpm)/Al (165 nm) was selected as the optimum structure with a minimum lightening voltage of 7. 1 V. The emission light ranged from 550 nm to 650 nm and was observed as an orange light.

At small Bjorken scaling variable x, dominated Glouns in a hadronic process becomes a color glass condensate (CGC) and most important principle in this subject is existence of a saturation scale. Then we can describe unintegrated gluon distribution function according to the saturation scale. In this study, we want to calculate gluon distribution function with respect of AdS/CFT correspondence. By using Fourier transform of diploe scattering amplitude, we can extract an analytical formula for the unintegrated gluon distribution function that inspired from AdS/CFT correspondences. Then our results compared with does from other parameterization models. These results show that the distribution function behavior tamed at low Bjorken scaling limit.

In this study based on Green’ s function formalism, we explore some aspects of the spin-dependent properties of a triple-quantum-dot ring structure. In this structure, one of the quantum dots has been considered to be non-magnetic and the Rashba spin-orbit interaction is imposed locally on this dot while the two others can be magnetic. Besides, it can be controlled the interference of electron waves in the output leads by tuning the parameters containing on-site energy of quantum dots, the magnetic flux penetrating inside the ring, the magnetic moment of dots and the Rashba spin-orbit interaction. The optimum parameters may lead to perfect splitting and polarization and simulate the Stern-Gerlach aparateus.

In this paper, we investigate triple properties of monolayer pentagon graphene that include electronic, magnetic and optical properties. Our research based on density functional theory (DFT) and the WIEN2k computational code is done. Our results show that in the electronic and magnetic properties, this structure with a direct gap energy of about 2. 2 eV along Г → Г direction and total magnetic moment of 0. 0013 μ B per unit cell is almost a non-magnetic semiconductor. Also, in the optical properties, the variation of optical parameters including dielectric constant, loss energy function and reflectivity in term of energy are drawn and studied. Its optical properties show that if this allotrope is used in solar cell technology, its efficiency in the low energy will be better because its loss energy function and reflectivity will be minimum.

In this paper, we will introduce soliton-like solutions of the complex ϕ ^6 system as an example of the complex non-linear Klein-Gordon systems in 1+1 dimensions. Complex kink (anti-kink), radiative profiles and wave-packets are three different types of soliton-like solutions for complex ϕ ^6 system. All relativistic energy-momentum relations can be satisfied generally for such solutions. For this special system, numerical calculations show that we can detect an apparent uncertainty in the outputs of collisions of the complex kink-anti-kink pairs and the pairs of wave-packets, which originate from an arbitrary initial phase. Also in collisions between out-of-phase kink-anti-kink pairs, we can always detect radiative profiles. The reverse can also occur, i. e. in collisions between two energetic radiative profiles with zero rest masses, it is possible to create a pair of kink-anti-kink with non-zero rest masses.

In this paper, the Lifshitz formula for the Casimir energy between two dielectrics in zero temperature is derived using box renormalization. Although there are several derivations for the force in this case in the literature, including Lifshitz’ s own proof, so far there has been no unambiguous and rigorous derivation for energy that we are aware of. Since energy becomes important in some cases, e. g. calculation of entropy or heat capacity, using the correct and precise definition of the Casimir energy, for the first time, we remove all of the infinities systematically without any ambiguity. This proof also shows the strength and accuracy of the box renormalization scheme.

In this work, Fe doped TiO2 nanoparticles at different Fe/Ti molar ratio from 1 to 10% and different annealing temperature from 400 to 800 oC were investigated by X-ray diffraction spectroscopy, transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). The size of prepared nanoparticles was estimated between 6 to 100 nm by transmission electron microscopy. The characterization by diffuse reflectance spectroscopy revealed that the optical absorption in the visible region significantly increased by doping of TiO2 nanoparticles. . The calculated gap energy by second derivative of Tauc plot demonstrated that the gap energy decreased to 2. 5 eV for samples at higher Fe content and annealing temperature.