Volume 57, Number 34, 2012
Theoretical Physics
Chiral Solitons with Bohm Potential by Lie Group Analysis and Traveling Wave Hypothesis A. G. Johnpillai, Ahmet Yildirim, Anjan Biswas Romanian Journal of Physics 57,
545554 (2012)
We study the chiral nonlinear Schrödinger's equation with Bohm potential by analyzing an equivalent system of nonlinear partial differential equations from the Lie symmetry point of view. These system of equations are obtained by decomposing the underlying equation into real and imaginary components. The Lie point symmetry generators of the system of equations with respect to zero and non zero values of the coefficient of the Bohm potential are obtained. The optimal system of onedimensional subalgebras of the Lie symmetry algebra of the system in each of the two cases are used to reduce the system of equations to a system of nonlinear first and secondorder ordinary differential equations. Exact groupinvariant solutions to the system of equations are constructed from the reduced system of ordinary differential equations.
Tripartite Entanglement Swapping of Continuous Variables DaoHua Wu Romanian Journal of Physics 57,
555563 (2012)
We propose a scheme for tripartite entanglement swapping of continuous variables, where one EPR pair and one local Wtype entangled state are utilized. Because of the coexistence of both bipartite and tripartite entanglement in a Wtype entangled state, one optical beams of the EPR state will be entangled with the output modes displaced by Bob and Claire. Actually, the entanglement swapping processing could be viewed as teleclone of entangled state of continuous variables.
Imperfect ManytoMany Teleportation Iulia Ghiu, Tudor Isdraila, Serban Suciu Romanian Journal of Physics 57,
564570 (2012)
We propose a generalization of the manytomany teleportation to the case when a nonmaximally quantum channel is shared between the senders and receivers and the measurements are performed by the senders in a modified Bell basis.
A Note on Proper Teleparallel Homothetic Vector Fields in Non Static Plane Symmetric Lorentzian Manifolds Ghulam Shabbir, Suhail Khan Romanian Journal of Physics 57,
571581 (2012)
In this paper we classify plane symmetric non static spacetimes according to their proper teleparallel homothetic vector fields using direct integration technique. It turns out that the dimensions of the teleparallel homothetic vector fields are 6, 7, 8 or 11. In the cases of 6, 7 or 8, proper teleparallel homothetic vector fields exist for the special choice of the spacetimes. In the case of 11 homothetic vector fields the spacetime becomes Minkowski and all the torsion components are zero. In the case of 11 homothetic vector fields the homothetic vector fields in both the theories are exactly the same.
Asymptotic Iteration Method Applied to BoundState Problems with Unbroken and Broken Supersymmetry O. Özer G. Lévai Romanian Journal of Physics 57,
582593 (2012)
The boundstate spectra for some potentials with unbroken and broken supersymmetry are investigated by the quantization condition of a method, called Asymptotic Iteration Method (AIM). Energy eigenvalues of the supersymmetric partner potentials are obtained. The present results are found to be in excellent agreement with numerical values. It is also noted that the AIM condition preserves the supersymmetric energy degeneracy, and generally fewer iteration steps are necessary to obtain the energy eigenvalues of the $V_+(x)$ “fermionic” potential with the same accuracy.
Nuclear Physics & High Energy Physics
MicroPixe and XRF Studies on Native Gold from Cavnic Ore Deposit (Baia Mare District) Daniela CristeaStan, B. Constantinescu, Catalina Chiojdeanu, D. Ceccato, Claire Pacheco, L. Pichon Romanian Journal of Physics 57,
594606 (2012)
MicroPIXE (2 MeV protons at AN2000 accelerator of Legnaro and 3 MeV protons at AGLAE accelerator of CNRSLouvre) and XRF were used for geochemical characterization of native gold from CavnicRoata mine (BaiaMare district). Elemental composition, Ag/(Au+Ag) ratios, trace elements (Te, Sb) suggesting gold minerals (tellurides) and associated minerals were determined.
Study of Backward Relativistic Hadron Emitted in ^{4}He and ^{7}Li Interactions with Emulsion Nuclei at about 2A GeV E. ElFalaky Romanian Journal of Physics 57,
607619 (2012)
A comprehensive study on $^4$He interactions with emulsion nuclei at (2.1A GeV) are carried out in comparison with those belonging to $^7$Li at nearby energy (2.2A GeV). Throughout, such investigation, two sufficient statistics of inelastic interaction events are picked up [$^4$He (2066) and $^7$Li (1003)]. The average experimental mean free paths for $^4$He and $^7$Li as well as the corresponding theoretical predicted values due to Glauber multiple scattering theory are presented. The general features of the two ion beams are caught using, the average multiplicities of different secondaries produced in the forward hemisphere of interactions FHS at ($\theta_{\mathrm{Lab.}} < 90^\circ$) and in backward hemisphere BHS at ($\theta_{\mathrm{Lab.}} \ge 90^\circ$). The multiplicity distributions of the produced relativistic particles are displayed. Checking up the effect of target size, impact parameter and centrality, representative parameters are used to categorize the statistical sample of events. In the light of the mentioned categories the study is processed. The experimental results are reviewed in the framework of the modified cascade model to identify its ability for application.
Condensed Matter
Conductivity of ThreeBarrier Resonance Tunnel Structure M. V. Tkach, Yu .O. Seti, O. M. Voitsekhivska, G. G. Zegrya Romanian Journal of Physics 57,
620629 (2012)
Within the model of rectangular potentials and different effective electron masses it is developed a theory and performed a quantummechanical calculation of dynamical conductivity for the electrons interacting with electromagnetic field in open threebarrier resonance tunnel structure with arbitrary outer barriers. For the experimentally investigated structure with In_{0.53}Ga_{0.47}Aswells and In_{0.52}Al_{0.48}Asbarriers, it is shown that there exist the optimal geometrical configurations determined by the position of the inner barrier respectively the outer ones, providing the optimal operation of nanodevice as a separate detector or an active element of such a detector in desired frequency range.
Pressure Dependence of the Superconducting State Parameters of Binary Metallic Glass Superconductor Ca_{70}Zn_{3} Aditya M. Vora Romanian Journal of Physics 57,
630644 (2012)
Theoretical computation of the pressure dependence superconducting state parameters of binary Ca_{70}Zn_{30} is reported using model potential formalism. Explicit expressions have been derived for the volume dependence of the electronphonon coupling strength λ and the Coulomb pseudopotential µ^{*} considering the variation of Fermi momentum k_{F} and Debye temperature θ_{D} with volume, if glasses in the considered system are superconducting or not in normal conditions. Well known Ashcroft’s empty core (EMC) model pseudopotential and five different types of the local field correction functions viz. Hartree (H), Taylor (T), IchimaruUtsumi (IU), Farid et al. (F) and Sarkar et al. (S) have been used for obtaining pressure dependence of transition temperature T_{C} and the logarithmic volume derivative Φ of the effective interaction strength N_{O}V for metallic glass superconductor.
Thermodynamic Properties of a Nematogen  A Computational Approach P. Lakshmi Praveen, Durga P. Ojha Romanian Journal of Physics 57,
645656 (2012)
Thermodynamic properties of a nematogen pnNonyloxybenzoic acid (9OBAC) have been carried out with respect to translational and orientational motions. The atomic net charge and dipole moment at each atomic center has been evaluated using the complete neglect differential overlap (CNDO/2) method. The modified Rayleigh–Schrödinger perturbation theory, along with multicenteredmultipole expansion method, has been employed to evaluate the longrange intermolecular interactions, while a ‘6exp’ potential function has been assumed for shortrange interactions. The total interaction energy values obtained through these computations have been used to calculate the thermodynamical properties such as entropy and Helmholtz free energy of each configuration at room temperature (300K), nematicisotropic transition (416K) and above transition temperature (550K). A comparative picture of molecular parameters such as total energy, binding energy, and total dipole moment of 9OBAC with other homologues pnOctyloxybenzoic acid (8OBAC) and pnDecyloxybenzoic acid (10OBAC) has been given. The present computations have been aimed at understanding the delicate balance between energy and entropy that causes the aggregation states of liquid crystalline systems and to develop new and interesting model for nematic phase stability at molecular level based on the thermodynamic properties introduced in this paper.
Defect Density Estimation in Nanocluster Carbon Thin Films Shounak De, B. S. Satyanarayana, Mohan Rao, V. H. S. Moorthy Romanian Journal of Physics 57,
657663 (2012)
Nanocluster carbon thin films were grown using the room temprature based cathodic arc process. These films are mixed phase material containing both sp^{2} and sp^{3} bondings. Spacechargelimitedcurrent conduction (SCLC) mechanism was investigated in the case of Nanocluster carbon thin films. The results were analyzed by assuming uniform density of traps near the Fermi level. The values of density of states at the Fermi level, g (E_{f}), have been obtained from the SCLC measurements ranges between 6x10^{17} cm^{3} eV^{1} to 8x10^{17} cm^{3} eV^{1}.
New Approach of the AC Electrode Polarization During the Measurements of Impedance Spectra C. P. Ganea Romanian Journal of Physics 57,
664675 (2012)
A mathematical approach for describing the influence of the ions dissolved in a liquid crystal on the impedance measurements is presented. New independent variables allow reformulating the basic coupled differential equations of continuity and Poisson equation as well. The obtained forms are simpler than those used up to now. Illustrative examples are analyzed.
Dynamical Response of a Multibody System with Flexible Elements with a General ThreeDimensional Motion S. Vlase Romanian Journal of Physics 57,
676693 (2012)
The technical applications of the last decades are characterized by high velocities and loads of mechanical components which lead to qualitative different mechanical phenomena mainly due to the elasticity of elements, (high deformations, resonance, stability). This paper aims at developing a onedimensional finite element with a threedimensional motion allowing the modeling of these mechanical systems.
Optics and Lasers
Squeezing in Hidden OpticalPolarization by Degenerate Parametric Amplifier Gyaneshwar K. Gupta, Lallan Yadava, Ravi S. Singh Romanian Journal of Physics 57,
694705 (2012)
Temporal evolution of monochromatic bimodal chaotic optical field, enriched with orthogonallypolarized basismodes propagating collinearly and undergoing Degenerate Parametric Amplification, is investigated to demonstrate Squeezing in Hidden OpticalPolarization. The Variance (Noise) of Hidden OpticalPolarization Parameters showcasing Squeezing therein is studied by identifying a Squeezing – Function. This squeezing in HOPS is seen to depend critically on an OnsetTime responsible for the same.
High Force Transducer at Nanoscale T. Vasile, C. Udrea, Mihaela Bojan, F. Garoi, V. Damian, D. Apostol Romanian Journal of Physics 57,
706710 (2012)
We have designed and experimented with a grating controlled actuator within nanometer scale. The proposed actuator consists of diffractive and thermoelectric components. The structure of the actuator and the principle of his motion are described. The high sensitivity and force are achieved by expanding a metallic diffraction grating.
The Lasing Wavelength of QW Active Region of AlGaAs SCH Lasers Zbigniew Koziol, Sergey I. Matyukhin Romanian Journal of Physics 57,
711719 (2012)
Computer simulations with Synopsys’ Sentaurus TCAD are used to study the effect of the molar concentration of aluminum in the active and waveguide regions on the energy spectrum of carriers in Quantum Well (QW) and the optical spectral characteristics of radiation of semiconductor lasers with Al_{x}Ga_{1−x}As double heterostructures and separate confinement (SCH). Wavelength of singlemode lasers is shown to be almost independent of the concentration of aluminum in the waveguide itself, in a wide range of aluminum content, but to depend mainly on Al concentrations in QW region.
Biophysics
Characterization of 3D Visualization Method for DNA Sequences Ali Reza Ashrafi, Parisa Farhami Romanian Journal of Physics 57,
720725 (2012)
A DNA sequence can be identified with a word over the alphabet W = {A, C, G, T}. He and Wang (2004) presented an algebraic method for analyzing DNA sequences. They proved that under a natural action of the symmetric group S_{4} on DNA matrices, αΠ = Πα, where $\alpha \in \mathrm{S}_4$ and Π is a DNA matrix constructed from a DNA sequence. In this paper, the general form of models, which are satisfied the mentioned equality, is obtained. It is shown that the Zcurve, Hcurve and Randić's model are special cases of this general form.
Enviornmental Physics
Assessment of Natural Radioactivity Levels and Radiation Hazards for Building Materials Used in Qassim Area, Saudi Arabia A. ElTaher Romanian Journal of Physics 57,
726735 (2012)
Building materials are one of the potential sources of indoor radioactivity because of the naturally occuring radionuclides in them. External as well as internal exposures are the two pathways of radiation dose imparted to the human beings from the building materials. Natural radioactivity levels of 35 samples of natural and manufactured building materials used in Qassim area, Saudi Arabia have been investigated by using gamma spectrometer with NaI(Tl) detector. The samples were collected from local market and construction sites. From the measured γray spectra, activity concentrations were determined. The activity ranged from 12.7 ±3.4 to 38.4 ±4.4 Bq kg^{1} for ^{226}Ra, from 13.2±0.7 to 49.2±2.3 Bq kg^{1} for ^{232}Th and from 64±3 to 340±6.7 Bq kg^{1} for ^{40}K. The activities are compared with available reported data from other countries and with the world average value for soils. The radium equivalent activity Raeq, the external hazard index Hex and the absorbed dose rate in air D in each sample was evaluated to assess the radiation hazard for people living in dwelling made of materials studied. All building materials have shwon Raeq ranged from 39.64 to 122.71 Bq kg^{1}. These values are lower than the limit of 370 Bq kg^{1} adopted by OECD the Organization for Economic Cooperation and Development. The absorbed dose rate in indoor air are lower than the international recommended values of 55 n Gy h^{1} for all test samples. All the materials examined are acceptable for use as building materials as defined by the OECD criterion.
Astrophysics
Gravitational Lensing by Wormholes Juan Manuel Tejeiro, Alexis Larranaga Romanian Journal of Physics 57,
736747 (2012)
Natural wormholes and its astrophysical signatures have been suggested in various opportunities. By applying the strong field limit of gravitational lensing theory, we calculate the deflection angle and magnification curves produced by MorrisThorne wormholes in asymptotically flat spacetimes. The results show that wormholes act like convergent lenses. Therefore, we show that it is hard to distinguish them from black holes using the deflection’s angle of the gravitational lens effect, in contrast with the results reported by Cramer et al. and Safanova et al.. However, we also show that it is possible, in principle, distinguish them by the magnification curves, in particular, by observing the position of the peak of the Einstein’s ring.
Bianchi TypeIII Cosmological Model with Variable G and ΛTerm in General Relativity Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan Romanian Journal of Physics 57,
748760 (2012)
Exact solution of Einstein's field equations with variable gravitational and cosmological ``constant'' is obtained in presence of perfect fluid for Bianchi III spacetime. To get the deterministic solution of the field equations the expansion $\theta$, in the model, is considered as proportional to the eigen value $\sigma^{2}_{~2}$ of the shear tensor $\sigma^{j}_{~i}$ and also the fluid obeys the barotropic equation of state. The value of cosmological constant $\Lambda$ for the model is found to be small and positive which is supported by the results from recent supernovae Ia observations. Moreover, it is observed that due to the combined effect of time variable $\Lambda$ and $G$ the universe evolved with deceleration as well as acceleration. The model shows that $G$ varies with time as suggested earlier by Large Number Hypothesis proposed by Dirac. It has been found that all physical and geometric parameters of the model are in fair agreement of observational results. Some physical and geometric properties of the model are also discussed.
Bulk Viscous Inhomogeneous Cosmological Models with Electromagnetic Field in Lyra Geometry Rashid Zia, R. P. Singh Romanian Journal of Physics 57,
761778 (2012)
A new class of exact solutions of Einstein's modified field equations in inhomogeneous spacetime for bulk viscous fluid distribution with electromagnetic field is obtained in the context of normal gauge for Lyra's manifold. We have obtained solutions by considering the time dependent displacement field. The source of magnetic field is due to an electric current produced along the zaxis. Only $F_{12}$ is a nonvanishing component of the electromagnetic field tensor. The coefficient of bulk viscosity is assumed to be a power function of the mass density. It has been found that the displacement vector behaves like the cosmological constant in the normal gauge treatment and the solutions are consistent with the recent observations of Type Ia supernovae. Physical and geometric aspects of the models are also discussed in the presence of magnetic field.
